diff --git a/app/Http/Requests/EstimatesRequest.php b/app/Http/Requests/EstimatesRequest.php
index 3c3dd45b..870e134c 100644
--- a/app/Http/Requests/EstimatesRequest.php
+++ b/app/Http/Requests/EstimatesRequest.php
@@ -5,6 +5,7 @@ namespace App\Http\Requests;
 use App\Models\CompanySetting;
 use App\Models\Customer;
 use App\Models\Estimate;
+use App\Support\DocumentTotals;
 use Illuminate\Foundation\Http\FormRequest;
 use Illuminate\Validation\Rule;
 
@@ -119,18 +120,34 @@ class EstimatesRequest extends FormRequest
         $exchange_rate = $company_currency != $current_currency ? $this->exchange_rate : 1;
         $currency = Customer::find($this->customer_id)->currency_id;
 
+        $tax_per_item = CompanySetting::getSetting('tax_per_item', $this->header('company')) ?? 'NO ';
+        $discount_per_item = CompanySetting::getSetting('discount_per_item', $this->header('company')) ?? 'NO';
+
+        // Recompute totals server-side from the line items (GHSA-8c69).
+        $totals = DocumentTotals::compute(
+            $this->items ?? [],
+            $this->taxes ?? [],
+            $this->discount_val,
+            $tax_per_item,
+            (bool) $this->tax_included,
+            $discount_per_item
+        );
+
         return collect($this->except('items', 'taxes'))
             ->merge([
                 'creator_id' => $this->user()->id ?? null,
                 'status' => $this->has('estimateSend') ? Estimate::STATUS_SENT : Estimate::STATUS_DRAFT,
                 'company_id' => $this->header('company'),
-                'tax_per_item' => CompanySetting::getSetting('tax_per_item', $this->header('company')) ?? 'NO ',
-                'discount_per_item' => CompanySetting::getSetting('discount_per_item', $this->header('company')) ?? 'NO',
+                'tax_per_item' => $tax_per_item,
+                'discount_per_item' => $discount_per_item,
+                'sub_total' => $totals['sub_total'],
+                'total' => $totals['total'],
+                'tax' => $totals['tax'],
                 'exchange_rate' => $exchange_rate,
                 'base_discount_val' => $this->discount_val * $exchange_rate,
-                'base_sub_total' => $this->sub_total * $exchange_rate,
-                'base_total' => $this->total * $exchange_rate,
-                'base_tax' => $this->tax * $exchange_rate,
+                'base_sub_total' => $totals['sub_total'] * $exchange_rate,
+                'base_total' => $totals['total'] * $exchange_rate,
+                'base_tax' => $totals['tax'] * $exchange_rate,
                 'currency_id' => $currency,
             ])
             ->toArray();
diff --git a/app/Http/Requests/InvoicesRequest.php b/app/Http/Requests/InvoicesRequest.php
index 48c5ac10..561db0f3 100644
--- a/app/Http/Requests/InvoicesRequest.php
+++ b/app/Http/Requests/InvoicesRequest.php
@@ -5,6 +5,7 @@ namespace App\Http\Requests;
 use App\Models\CompanySetting;
 use App\Models\Customer;
 use App\Models\Invoice;
+use App\Support\DocumentTotals;
 use Illuminate\Foundation\Http\FormRequest;
 use Illuminate\Validation\Rule;
 
@@ -118,23 +119,41 @@ class InvoicesRequest extends FormRequest
         $exchange_rate = $company_currency != $current_currency ? $this->exchange_rate : 1;
         $currency = Customer::find($this->customer_id)->currency_id;
 
+        $tax_per_item = CompanySetting::getSetting('tax_per_item', $this->header('company')) ?? 'NO ';
+        $discount_per_item = CompanySetting::getSetting('discount_per_item', $this->header('company')) ?? 'NO';
+
+        // Recompute the document totals server-side from the line items so a
+        // tampered total/sub_total/tax/due_amount in the request is ignored
+        // (GHSA-8c69).
+        $totals = DocumentTotals::compute(
+            $this->items ?? [],
+            $this->taxes ?? [],
+            $this->discount_val,
+            $tax_per_item,
+            (bool) $this->tax_included,
+            $discount_per_item
+        );
+
         return collect($this->except('items', 'taxes'))
             ->merge([
                 'creator_id' => $this->user()->id ?? null,
                 'status' => $this->has('invoiceSend') ? Invoice::STATUS_SENT : Invoice::STATUS_DRAFT,
                 'paid_status' => Invoice::STATUS_UNPAID,
                 'company_id' => $this->header('company'),
-                'tax_per_item' => CompanySetting::getSetting('tax_per_item', $this->header('company')) ?? 'NO ',
-                'discount_per_item' => CompanySetting::getSetting('discount_per_item', $this->header('company')) ?? 'NO',
-                'due_amount' => $this->total,
+                'tax_per_item' => $tax_per_item,
+                'discount_per_item' => $discount_per_item,
+                'sub_total' => $totals['sub_total'],
+                'total' => $totals['total'],
+                'tax' => $totals['tax'],
+                'due_amount' => $totals['total'],
                 'sent' => (bool) $this->sent ?? false,
                 'viewed' => (bool) $this->viewed ?? false,
                 'exchange_rate' => $exchange_rate,
-                'base_total' => $this->total * $exchange_rate,
+                'base_total' => $totals['total'] * $exchange_rate,
                 'base_discount_val' => $this->discount_val * $exchange_rate,
-                'base_sub_total' => $this->sub_total * $exchange_rate,
-                'base_tax' => $this->tax * $exchange_rate,
-                'base_due_amount' => $this->total * $exchange_rate,
+                'base_sub_total' => $totals['sub_total'] * $exchange_rate,
+                'base_tax' => $totals['tax'] * $exchange_rate,
+                'base_due_amount' => $totals['total'] * $exchange_rate,
                 'currency_id' => $currency,
             ])
             ->toArray();
diff --git a/app/Http/Requests/RecurringInvoiceRequest.php b/app/Http/Requests/RecurringInvoiceRequest.php
index f9792832..e5cd7d08 100644
--- a/app/Http/Requests/RecurringInvoiceRequest.php
+++ b/app/Http/Requests/RecurringInvoiceRequest.php
@@ -5,6 +5,7 @@ namespace App\Http\Requests;
 use App\Models\CompanySetting;
 use App\Models\Customer;
 use App\Models\RecurringInvoice;
+use App\Support\DocumentTotals;
 use Illuminate\Foundation\Http\FormRequest;
 
 class RecurringInvoiceRequest extends FormRequest
@@ -106,15 +107,35 @@ class RecurringInvoiceRequest extends FormRequest
 
         $nextInvoiceAt = RecurringInvoice::getNextInvoiceDate($this->frequency, $this->starts_at);
 
+        $tax_per_item = CompanySetting::getSetting('tax_per_item', $this->header('company')) ?? 'NO ';
+        $discount_per_item = CompanySetting::getSetting('discount_per_item', $this->header('company')) ?? 'NO';
+
+        // Recompute totals server-side from the line items (GHSA-8c69). The
+        // recurring template totals propagate to every generated invoice.
+        $totals = DocumentTotals::compute(
+            $this->items ?? [],
+            $this->taxes ?? [],
+            $this->discount_val,
+            $tax_per_item,
+            (bool) $this->tax_included,
+            $discount_per_item
+        );
+
         return collect($this->except('items', 'taxes'))
             ->merge([
                 'creator_id' => $this->user()->id,
                 'company_id' => $this->header('company'),
                 'next_invoice_at' => $nextInvoiceAt,
-                'tax_per_item' => CompanySetting::getSetting('tax_per_item', $this->header('company')) ?? 'NO ',
-                'discount_per_item' => CompanySetting::getSetting('discount_per_item', $this->header('company')) ?? 'NO',
-                'due_amount' => $this->total,
+                'tax_per_item' => $tax_per_item,
+                'discount_per_item' => $discount_per_item,
+                'sub_total' => $totals['sub_total'],
+                'total' => $totals['total'],
+                'tax' => $totals['tax'],
+                'due_amount' => $totals['total'],
                 'exchange_rate' => $exchange_rate,
+                'base_sub_total' => $totals['sub_total'] * $exchange_rate,
+                'base_total' => $totals['total'] * $exchange_rate,
+                'base_tax' => $totals['tax'] * $exchange_rate,
                 'currency_id' => $currency,
             ])
             ->toArray();
diff --git a/app/Models/Estimate.php b/app/Models/Estimate.php
index 8ebe1f15..3806859b 100644
--- a/app/Models/Estimate.php
+++ b/app/Models/Estimate.php
@@ -8,6 +8,7 @@ use App\Facades\PDF;
 use App\Mail\SendEstimateMail;
 use App\Services\SerialNumberFormatter;
 use App\Space\PdfTemplateUtils;
+use App\Support\DocumentTotals;
 use App\Support\SafeOrderBy;
 use App\Traits\GeneratesPdfTrait;
 use App\Traits\HasCustomFieldsTrait;
@@ -317,6 +318,8 @@ class Estimate extends Model implements HasMedia
         foreach ($estimateItems as $estimateItem) {
             $estimateItem['company_id'] = $request->header('company');
             $estimateItem['exchange_rate'] = $exchange_rate;
+            // Recompute the item total from price/quantity (GHSA-8c69).
+            $estimateItem['total'] = DocumentTotals::itemTotal($estimateItem, $estimate->discount_per_item === 'YES');
             $estimateItem['base_price'] = $estimateItem['price'] * $exchange_rate;
             $estimateItem['base_discount_val'] = $estimateItem['discount_val'] * $exchange_rate;
             $estimateItem['base_tax'] = $estimate['tax'] * $exchange_rate;
diff --git a/app/Models/Invoice.php b/app/Models/Invoice.php
index e92f24ec..f8f1c9d6 100644
--- a/app/Models/Invoice.php
+++ b/app/Models/Invoice.php
@@ -8,6 +8,7 @@ use App\Facades\PDF;
 use App\Mail\SendInvoiceMail;
 use App\Services\SerialNumberFormatter;
 use App\Space\PdfTemplateUtils;
+use App\Support\DocumentTotals;
 use App\Support\SafeOrderBy;
 use App\Traits\GeneratesPdfTrait;
 use App\Traits\HasCustomFieldsTrait;
@@ -392,12 +393,12 @@ class Invoice extends Model implements HasMedia
             return 'customer_cannot_be_changed_after_payment_is_added';
         }
 
-        if ($request->total >= 0 && $request->total < $total_paid_amount) {
+        if ($data['total'] >= 0 && $data['total'] < $total_paid_amount) {
             return 'total_invoice_amount_must_be_more_than_paid_amount';
         }
 
-        if ($oldTotal != $request->total) {
-            $oldTotal = (int) round($request->total) - (int) $oldTotal;
+        if ($oldTotal != $data['total']) {
+            $oldTotal = (int) round($data['total']) - (int) $oldTotal;
         } else {
             $oldTotal = 0;
         }
@@ -506,6 +507,9 @@ class Invoice extends Model implements HasMedia
         foreach ($invoiceItems as $invoiceItem) {
             $invoiceItem['company_id'] = $invoice->company_id;
             $invoiceItem['exchange_rate'] = $exchange_rate;
+            // Recompute the item total from price/quantity so a tampered item
+            // total can't desync from the recomputed document totals (GHSA-8c69).
+            $invoiceItem['total'] = DocumentTotals::itemTotal($invoiceItem, $invoice->discount_per_item === 'YES');
             $invoiceItem['base_price'] = $invoiceItem['price'] * $exchange_rate;
             $invoiceItem['base_discount_val'] = $invoiceItem['discount_val'] * $exchange_rate;
             $invoiceItem['base_tax'] = $invoiceItem['tax'] * $exchange_rate;
diff --git a/app/Models/RecurringInvoice.php b/app/Models/RecurringInvoice.php
index d44f5e36..0695102f 100644
--- a/app/Models/RecurringInvoice.php
+++ b/app/Models/RecurringInvoice.php
@@ -5,6 +5,7 @@ namespace App\Models;
 use App\Facades\Hashids;
 use App\Http\Requests\RecurringInvoiceRequest;
 use App\Services\SerialNumberFormatter;
+use App\Support\DocumentTotals;
 use App\Support\SafeOrderBy;
 use App\Traits\HasCustomFieldsTrait;
 use Carbon\Carbon;
@@ -248,6 +249,8 @@ class RecurringInvoice extends Model
     {
         foreach ($invoiceItems as $invoiceItem) {
             $invoiceItem['company_id'] = $recurringInvoice->company_id;
+            // Recompute the item total from price/quantity (GHSA-8c69).
+            $invoiceItem['total'] = DocumentTotals::itemTotal($invoiceItem, $recurringInvoice->discount_per_item === 'YES');
             $item = $recurringInvoice->items()->create($invoiceItem);
             if (array_key_exists('taxes', $invoiceItem) && $invoiceItem['taxes']) {
                 foreach ($invoiceItem['taxes'] as $tax) {
diff --git a/app/Support/DocumentTotals.php b/app/Support/DocumentTotals.php
new file mode 100644
index 00000000..d626ec01
--- /dev/null
+++ b/app/Support/DocumentTotals.php
@@ -0,0 +1,70 @@
+<?php
+
+namespace App\Support;
+
+/**
+ * Recomputes authoritative invoice/estimate/recurring-invoice totals from the
+ * submitted line items + document-level discount/taxes, mirroring the
+ * front-end calculation (resources/scripts/admin/stores/invoice.js and
+ * components/estimate-invoice-common/CreateItemRow.vue).
+ *
+ * The client-supplied total / sub_total / tax / due_amount are NOT trusted
+ * (GHSA-8c69) — only price, quantity, discounts and tax-line amounts are.
+ * All amounts are integer minor units (cents).
+ */
+class DocumentTotals
+{
+    /**
+     * @param  array  $items  each item: price, quantity, discount_val?, taxes?[{amount}]
+     * @param  array  $taxes  document-level taxes: [{amount}, ...]
+     * @return array{sub_total:int, tax:int, total:int}
+     */
+    public static function compute(array $items, array $taxes, $discountVal, $taxPerItem, bool $taxIncluded, $discountPerItem = 'NO'): array
+    {
+        $perItemDiscount = is_string($discountPerItem) && strtoupper(trim($discountPerItem)) === 'YES';
+        $perItemTax = is_string($taxPerItem) && strtoupper(trim($taxPerItem)) === 'YES';
+
+        $subTotal = 0;
+        $itemTaxTotal = 0;
+
+        foreach ($items as $item) {
+            $subTotal += self::itemTotal($item, $perItemDiscount);
+            $itemTaxTotal += self::sumTaxAmounts($item['taxes'] ?? []);
+        }
+
+        $subtotalWithDiscount = $subTotal - (int) round((float) $discountVal);
+
+        $totalTax = $perItemTax ? $itemTaxTotal : self::sumTaxAmounts($taxes);
+
+        $total = $taxIncluded ? $subtotalWithDiscount : $subtotalWithDiscount + $totalTax;
+
+        return [
+            'sub_total' => $subTotal,
+            'tax' => $totalTax,
+            'total' => $total,
+        ];
+    }
+
+    /**
+     * Authoritative per-item total: round(price * quantity) minus the item
+     * discount (only applied when discount is configured per item).
+     */
+    public static function itemTotal(array $item, bool $perItemDiscount): int
+    {
+        $price = (float) ($item['price'] ?? 0);
+        $quantity = (float) ($item['quantity'] ?? 0);
+        $discount = $perItemDiscount ? (int) round((float) ($item['discount_val'] ?? 0)) : 0;
+
+        return (int) round($price * $quantity) - $discount;
+    }
+
+    protected static function sumTaxAmounts(array $taxes): int
+    {
+        $sum = 0;
+        foreach ($taxes as $tax) {
+            $sum += (int) round((float) ($tax['amount'] ?? 0));
+        }
+
+        return $sum;
+    }
+}
diff --git a/tests/Feature/Admin/EstimateTest.php b/tests/Feature/Admin/EstimateTest.php
index ef42c27d..fb0057ad 100644
--- a/tests/Feature/Admin/EstimateTest.php
+++ b/tests/Feature/Admin/EstimateTest.php
@@ -57,12 +57,9 @@ test('create estimate', function () {
         'estimate_number' => $estimate['estimate_number'],
         'discount_type' => $estimate['discount_type'],
         'discount_val' => $estimate['discount_val'],
-        'sub_total' => $estimate['sub_total'],
         'discount' => $estimate['discount'],
         'customer_id' => $estimate['customer_id'],
-        'total' => $estimate['total'],
         'notes' => $estimate['notes'],
-        'tax' => $estimate['tax'],
     ]);
 });
 
@@ -115,12 +112,9 @@ test('update estimate', function () {
         'estimate_number' => $estimate2['estimate_number'],
         'discount_type' => $estimate2['discount_type'],
         'discount_val' => $estimate2['discount_val'],
-        'sub_total' => $estimate2['sub_total'],
         'discount' => $estimate2['discount'],
         'customer_id' => $estimate2['customer_id'],
-        'total' => $estimate2['total'],
         'notes' => $estimate2['notes'],
-        'tax' => $estimate2['tax'],
     ]);
 
     $this->assertDatabaseHas('estimate_items', [
@@ -319,12 +313,9 @@ test('create estimate with tax per item', function () {
         'estimate_number' => $estimate['estimate_number'],
         'discount_type' => $estimate['discount_type'],
         'discount_val' => $estimate['discount_val'],
-        'sub_total' => $estimate['sub_total'],
         'discount' => $estimate['discount'],
         'customer_id' => $estimate['customer_id'],
-        'total' => $estimate['total'],
         'notes' => $estimate['notes'],
-        'tax' => $estimate['tax'],
     ]);
 
     $this->assertDatabaseHas('estimate_items', [
@@ -378,12 +369,9 @@ test('create estimate with EUR currency', function () {
         'estimate_number' => $estimate['estimate_number'],
         'discount_type' => $estimate['discount_type'],
         'discount_val' => $estimate['discount_val'],
-        'sub_total' => $estimate['sub_total'],
         'discount' => $estimate['discount'],
         'customer_id' => $estimate['customer_id'],
-        'total' => $estimate['total'],
         'notes' => $estimate['notes'],
-        'tax' => $estimate['tax'],
     ]);
 
     $this->assertDatabaseHas('taxes', [
diff --git a/tests/Feature/Admin/InvoiceTest.php b/tests/Feature/Admin/InvoiceTest.php
index 99d9c4dc..42e203a3 100644
--- a/tests/Feature/Admin/InvoiceTest.php
+++ b/tests/Feature/Admin/InvoiceTest.php
@@ -48,11 +48,7 @@ test('create invoice', function () {
     $this->assertDatabaseHas('invoices', [
         'template_name' => $invoice['template_name'],
         'invoice_number' => $invoice['invoice_number'],
-        'sub_total' => $invoice['sub_total'],
-        'discount' => $invoice['discount'],
         'customer_id' => $invoice['customer_id'],
-        'total' => $invoice['total'],
-        'tax' => $invoice['tax'],
     ]);
 
     $this->assertDatabaseHas('invoice_items', [
@@ -61,6 +57,44 @@ test('create invoice', function () {
     ]);
 });
 
+test('server recomputes invoice totals and ignores client-supplied amounts', function () {
+    // Well-formed item (10 x 10000 = 100000) but every client-supplied total is
+    // tampered to 1 — the server must recompute from price/quantity (GHSA-8c69).
+    $item = InvoiceItem::factory()->raw([
+        'price' => 10000,
+        'quantity' => 10,
+        'total' => 1,
+        'discount_val' => 0,
+        'tax' => 0,
+        'taxes' => [],
+    ]);
+
+    $invoice = Invoice::factory()->raw([
+        'items' => [$item],
+        'taxes' => [],
+        'discount_val' => 0,
+        'tax_included' => false,
+        'sub_total' => 1,
+        'total' => 1,
+        'tax' => 0,
+        'due_amount' => 1,
+    ]);
+
+    postJson('api/v1/invoices', $invoice)->assertOk();
+
+    $this->assertDatabaseHas('invoices', [
+        'invoice_number' => $invoice['invoice_number'],
+        'sub_total' => 100000,
+        'total' => 100000,
+        'due_amount' => 100000,
+    ]);
+
+    $this->assertDatabaseHas('invoice_items', [
+        'name' => $item['name'],
+        'total' => 100000,
+    ]);
+});
+
 test('create invoice with negative and zero item quantities', function () {
     $invoice = Invoice::factory()->raw([
         'items' => [
@@ -77,6 +111,7 @@ test('create invoice with negative and zero item quantities', function () {
                 'price' => 75,
             ]),
         ],
+        'discount_val' => 0,
         'sub_total' => -150,
         'total' => -150,
     ]);
@@ -135,10 +170,6 @@ test('create invoice as sent', function () {
 
     $this->assertDatabaseHas('invoices', [
         'invoice_number' => $invoice['invoice_number'],
-        'sub_total' => $invoice['sub_total'],
-        'total' => $invoice['total'],
-        'tax' => $invoice['tax'],
-        'discount' => $invoice['discount'],
         'customer_id' => $invoice['customer_id'],
         'template_name' => $invoice['template_name'],
     ]);
@@ -173,10 +204,6 @@ test('update invoice', function () {
 
     $this->assertDatabaseHas('invoices', [
         'invoice_number' => $invoice2['invoice_number'],
-        'sub_total' => $invoice2['sub_total'],
-        'total' => $invoice2['total'],
-        'tax' => $invoice2['tax'],
-        'discount' => $invoice2['discount'],
         'customer_id' => $invoice2['customer_id'],
         'template_name' => $invoice2['template_name'],
     ]);
@@ -332,10 +359,6 @@ test('create invoice with negative tax', function () {
 
     $this->assertDatabaseHas('invoices', [
         'invoice_number' => $invoice['invoice_number'],
-        'sub_total' => $invoice['sub_total'],
-        'total' => $invoice['total'],
-        'tax' => $invoice['tax'],
-        'discount' => $invoice['discount'],
         'customer_id' => $invoice['customer_id'],
     ]);
 
@@ -368,10 +391,6 @@ test('create invoice with tax per item', function () {
 
     $this->assertDatabaseHas('invoices', [
         'invoice_number' => $invoice['invoice_number'],
-        'sub_total' => $invoice['sub_total'],
-        'total' => $invoice['total'],
-        'tax' => $invoice['tax'],
-        'discount' => $invoice['discount'],
         'customer_id' => $invoice['customer_id'],
     ]);
 
diff --git a/tests/Unit/DocumentTotalsTest.php b/tests/Unit/DocumentTotalsTest.php
new file mode 100644
index 00000000..c1f09358
--- /dev/null
+++ b/tests/Unit/DocumentTotalsTest.php
@@ -0,0 +1,79 @@
+<?php
+
+use App\Support\DocumentTotals;
+
+test('sums item totals from price and quantity, ignoring client-supplied item totals', function () {
+    $totals = DocumentTotals::compute(
+        [['price' => 10000, 'quantity' => 10, 'total' => 1, 'taxes' => []]],
+        [], 0, 'NO', false, 'NO'
+    );
+
+    expect($totals['sub_total'])->toBe(100000)
+        ->and($totals['total'])->toBe(100000)
+        ->and($totals['tax'])->toBe(0);
+});
+
+test('applies document discount and document-level tax', function () {
+    $totals = DocumentTotals::compute(
+        [['price' => 1000, 'quantity' => 2]],
+        [['amount' => 150]],
+        500, 'NO', false, 'NO'
+    );
+
+    // 2000 - 500 + 150
+    expect($totals['sub_total'])->toBe(2000)
+        ->and($totals['tax'])->toBe(150)
+        ->and($totals['total'])->toBe(1650);
+});
+
+test('uses per-item taxes (not document taxes) when tax_per_item is YES', function () {
+    $totals = DocumentTotals::compute(
+        [
+            ['price' => 1000, 'quantity' => 1, 'taxes' => [['amount' => 100]]],
+            ['price' => 2000, 'quantity' => 1, 'taxes' => [['amount' => 200]]],
+        ],
+        [['amount' => 9999]],
+        0, 'YES', false, 'YES'
+    );
+
+    expect($totals['sub_total'])->toBe(3000)
+        ->and($totals['tax'])->toBe(300)
+        ->and($totals['total'])->toBe(3300);
+});
+
+test('excludes tax from total when tax_included', function () {
+    $totals = DocumentTotals::compute(
+        [['price' => 1000, 'quantity' => 1]],
+        [['amount' => 100]],
+        0, 'NO', true, 'NO'
+    );
+
+    expect($totals['total'])->toBe(1000)->and($totals['tax'])->toBe(100);
+});
+
+test('applies per-item discount only when discount_per_item is YES', function () {
+    $with = DocumentTotals::compute(
+        [['price' => 1000, 'quantity' => 2, 'discount_val' => 300]],
+        [], 0, 'NO', false, 'YES'
+    );
+    $without = DocumentTotals::compute(
+        [['price' => 1000, 'quantity' => 2, 'discount_val' => 300]],
+        [], 0, 'NO', false, 'NO'
+    );
+
+    expect($with['sub_total'])->toBe(1700)
+        ->and($without['sub_total'])->toBe(2000);
+});
+
+test('supports negative quantities', function () {
+    $totals = DocumentTotals::compute(
+        [
+            ['price' => 100, 'quantity' => -2],
+            ['price' => 50, 'quantity' => 1],
+            ['price' => 75, 'quantity' => 0],
+        ],
+        [], 0, 'NO', false, 'NO'
+    );
+
+    expect($totals['sub_total'])->toBe(-150)->and($totals['total'])->toBe(-150);
+});
diff --git a/tests/Unit/EstimateTest.php b/tests/Unit/EstimateTest.php
index 316d9a8b..4d0e1425 100644
--- a/tests/Unit/EstimateTest.php
+++ b/tests/Unit/EstimateTest.php
@@ -66,12 +66,9 @@ test('create estimate', function () {
         'estimate_number' => $estimate['estimate_number'],
         'customer_id' => $estimate['customer_id'],
         'template_name' => $estimate['template_name'],
-        'sub_total' => $estimate['sub_total'],
-        'total' => $estimate['total'],
         'discount' => $estimate['discount'],
         'discount_type' => $estimate['discount_type'],
         'discount_val' => $estimate['discount_val'],
-        'tax' => $estimate['tax'],
         'notes' => $estimate['notes'],
     ]);
 });
@@ -114,12 +111,9 @@ test('update estimate', function () {
         'estimate_number' => $newEstimate['estimate_number'],
         'customer_id' => $newEstimate['customer_id'],
         'template_name' => $newEstimate['template_name'],
-        'sub_total' => $newEstimate['sub_total'],
-        'total' => $newEstimate['total'],
         'discount' => $newEstimate['discount'],
         'discount_type' => $newEstimate['discount_type'],
         'discount_val' => $newEstimate['discount_val'],
-        'tax' => $newEstimate['tax'],
         'notes' => $newEstimate['notes'],
     ]);
 });
diff --git a/tests/Unit/InvoiceTest.php b/tests/Unit/InvoiceTest.php
index e5ecb92e..68db6b90 100644
--- a/tests/Unit/InvoiceTest.php
+++ b/tests/Unit/InvoiceTest.php
@@ -82,9 +82,6 @@ test('create invoice', function () {
 
     $this->assertDatabaseHas('invoices', [
         'invoice_number' => $invoice['invoice_number'],
-        'sub_total' => $invoice['sub_total'],
-        'total' => $invoice['total'],
-        'tax' => $invoice['tax'],
         'discount' => $invoice['discount'],
         'notes' => $invoice['notes'],
         'customer_id' => $invoice['customer_id'],
@@ -133,9 +130,6 @@ test('update invoice', function () {
 
     $this->assertDatabaseHas('invoices', [
         'invoice_number' => $newInvoice['invoice_number'],
-        'sub_total' => $newInvoice['sub_total'],
-        'total' => $newInvoice['total'],
-        'tax' => $newInvoice['tax'],
         'discount' => $newInvoice['discount'],
         'notes' => $newInvoice['notes'],
         'customer_id' => $newInvoice['customer_id'],