diff --git a/tests/Feature/Accessories/Api/AdjustAccessoryQuantityApiTest.php b/tests/Feature/Accessories/Api/AdjustAccessoryQuantityApiTest.php
index 5f8c603e60..484c3b91fc 100644
--- a/tests/Feature/Accessories/Api/AdjustAccessoryQuantityApiTest.php
+++ b/tests/Feature/Accessories/Api/AdjustAccessoryQuantityApiTest.php
@@ -50,7 +50,7 @@ class AdjustAccessoryQuantityApiTest extends TestCase
         $this->assertSame('restock from PO', $log->note);
         // order_number moved off the log row to the Orders table — the
         // log carries order_id pointing at the newly-created Order.
-        $order = \App\Models\Order::findOrFail($log->order_id);
+        $order = $log->orderItem->order;
         $this->assertSame('PO-API-1', $order->order_number);
         $this->assertSame($actor->id, (int) $log->created_by);
     }
@@ -163,4 +163,118 @@ class AdjustAccessoryQuantityApiTest extends TestCase
             ->count(), 'No separate uploaded log entry should have been created.');
         $this->assertSame($uploadsBefore + 1, $accessory->uploads()->count());
     }
+
+    public function test_supplier_purchase_date_unit_cost_and_currency_land_on_order_and_order_item()
+    {
+        $accessory = Accessory::factory()->create(['qty' => 2]);
+        $supplier = \App\Models\Supplier::factory()->create();
+
+        $this->actingAsForApi(User::factory()->editAccessories()->create())
+            ->postJson(route('api.accessories.adjust-quantity', $accessory), [
+                'amount' => 5,
+                'note' => 'PO arrived',
+                'order_number' => 'PO-FULL-META',
+                'supplier_id' => $supplier->id,
+                'purchase_date' => '2026-03-15',
+                'unit_cost' => 12.3456,
+                'currency' => 'EUR',
+            ])
+            ->assertOk();
+
+        $log = Actionlog::where('item_type', Accessory::class)
+            ->where('item_id', $accessory->id)
+            ->where('action_type', ActionType::QuantityAdjust->value)
+            ->latest('id')
+            ->firstOrFail();
+
+        $order = $log->orderItem->order;
+        $this->assertSame('PO-FULL-META', $order->order_number);
+        $this->assertSame($supplier->id, (int) $order->supplier_id);
+        $this->assertSame('2026-03-15', $order->purchase_date->toDateString());
+        $this->assertSame('EUR', $order->currency);
+
+        $line = $order->orderItems()->firstOrFail();
+        $this->assertSame(Accessory::class, $line->item_type);
+        $this->assertSame($accessory->id, (int) $line->item_id);
+        $this->assertSame(5, (int) $line->qty);
+        $this->assertEquals(12.3456, (float) $line->price);
+    }
+
+    public function test_audit_only_zero_delta_with_no_order_metadata_skips_order_creation()
+    {
+        // Zero delta and no supplier / order number / date / cost /
+        // currency = pure inventory audit. No Order row should be
+        // created for these, since there was no transaction.
+        $accessory = Accessory::factory()->create(['qty' => 5]);
+        $ordersBefore = \App\Models\Order::count();
+
+        $this->actingAsForApi(User::factory()->editAccessories()->create())
+            ->postJson(route('api.accessories.adjust-quantity', $accessory), [
+                'amount' => 0,
+                'note' => 'shelf count matches',
+            ])
+            ->assertOk();
+
+        $this->assertSame($ordersBefore, \App\Models\Order::count());
+
+        $log = Actionlog::where('item_type', Accessory::class)
+            ->where('item_id', $accessory->id)
+            ->where('action_type', ActionType::QuantityAdjust->value)
+            ->latest('id')
+            ->firstOrFail();
+
+        $this->assertNull($log->order_item_id);
+    }
+
+    public function test_multiple_adjusts_with_same_order_number_dedupe_to_one_order()
+    {
+        // Repeated qty adjusts referencing the same order_number should
+        // reuse the existing Order row (dedupe on order_number +
+        // supplier + company), while each adjust still produces its own
+        // OrderItem line (one line per event).
+        $accessory = Accessory::factory()->create(['qty' => 0]);
+        $supplier = \App\Models\Supplier::factory()->create();
+        $actor = User::factory()->editAccessories()->create();
+
+        foreach ([3, 4] as $delta) {
+            $this->actingAsForApi($actor)
+                ->postJson(route('api.accessories.adjust-quantity', $accessory), [
+                    'amount' => $delta,
+                    'note' => 'staggered receipt',
+                    'order_number' => 'PO-DEDUPE',
+                    'supplier_id' => $supplier->id,
+                ])
+                ->assertOk();
+        }
+
+        $orders = \App\Models\Order::where('order_number', 'PO-DEDUPE')->get();
+        $this->assertCount(1, $orders, 'Same order_number should reuse the existing Order row.');
+
+        $items = $orders->first()->orderItems;
+        $this->assertCount(2, $items, 'Each adjust event should have its own OrderItem line.');
+        $this->assertEqualsCanonicalizing([3, 4], $items->pluck('qty')->map(fn ($q) => (int) $q)->all());
+    }
+
+    public function test_blank_order_number_creates_a_distinct_order_per_event()
+    {
+        // A blank order_number is a distinct transaction each time, not
+        // a bucket to pool anonymous receipts into. Each adjust with
+        // no order_number gets its own Order row.
+        $accessory = Accessory::factory()->create(['qty' => 0]);
+        $supplier = \App\Models\Supplier::factory()->create();
+        $actor = User::factory()->editAccessories()->create();
+        $ordersBefore = \App\Models\Order::count();
+
+        foreach ([2, 3] as $delta) {
+            $this->actingAsForApi($actor)
+                ->postJson(route('api.accessories.adjust-quantity', $accessory), [
+                    'amount' => $delta,
+                    'note' => 'anonymous receipt',
+                    'supplier_id' => $supplier->id,
+                ])
+                ->assertOk();
+        }
+
+        $this->assertSame($ordersBefore + 2, \App\Models\Order::count());
+    }
 }
diff --git a/tests/Feature/Accessories/Api/UpdateAccessoryTest.php b/tests/Feature/Accessories/Api/UpdateAccessoryTest.php
index 6d735fc91e..df2b526e92 100644
--- a/tests/Feature/Accessories/Api/UpdateAccessoryTest.php
+++ b/tests/Feature/Accessories/Api/UpdateAccessoryTest.php
@@ -185,7 +185,7 @@ class UpdateAccessoryTest extends TestCase implements TestsFullMultipleCompanies
             ->firstOrFail();
 
         $this->assertSame(7, (int) $log->quantity);
-        $this->assertSame('PO-API', \App\Models\Order::findOrFail($log->order_id)->order_number);
+        $this->assertSame('PO-API', $log->orderItem->order->order_number);
         $this->assertNotEmpty($log->note, 'Adjustment note must be synthesized when the API caller omits one');
     }
 
diff --git a/tests/Feature/Accessories/Ui/AdjustAccessoryQuantityTest.php b/tests/Feature/Accessories/Ui/AdjustAccessoryQuantityTest.php
index ca4d3d0f86..797b502ad9 100644
--- a/tests/Feature/Accessories/Ui/AdjustAccessoryQuantityTest.php
+++ b/tests/Feature/Accessories/Ui/AdjustAccessoryQuantityTest.php
@@ -51,7 +51,7 @@ class AdjustAccessoryQuantityTest extends TestCase
         $this->assertNotNull($log);
         $this->assertSame(3, (int) $log->quantity);
         $this->assertSame('restock from PO', $log->note);
-        $this->assertSame('PO-42', \App\Models\Order::findOrFail($log->order_id)->order_number);
+        $this->assertSame('PO-42', $log->orderItem->order->order_number);
         $this->assertSame($actor->id, (int) $log->created_by);
     }
 
@@ -76,7 +76,7 @@ class AdjustAccessoryQuantityTest extends TestCase
             ->first();
 
         $this->assertSame(-4, (int) $log->quantity);
-        $this->assertNull($log->order_id);
+        $this->assertNull($log->order_item_id);
     }
 
     public function test_decrement_below_zero_is_rejected()
diff --git a/tests/Feature/Assets/Api/StoreAssetTest.php b/tests/Feature/Assets/Api/StoreAssetTest.php
index 9614dd2a4b..87a6ab8711 100644
--- a/tests/Feature/Assets/Api/StoreAssetTest.php
+++ b/tests/Feature/Assets/Api/StoreAssetTest.php
@@ -74,10 +74,7 @@ class StoreAssetTest extends TestCase
         $this->assertTrue($asset->model->is($model));
         $this->assertEquals('A New Asset', $asset->name);
         $this->assertEquals('Some notes', $asset->notes);
-        // order_number moved off the parent Asset column to the Orders /
-        // OrderItems data model. A create-time order_number in the request
-        // body no longer lands on the model — acquisition tracking is via
-        // the adjust-quantity flow or the CSV importer.
+        $this->assertEquals('5678', $asset->order_number);
         $this->assertEquals('123.45', $asset->purchase_cost);
         $this->assertTrue($asset->purchase_date->is('2023-09-02'));
         $this->assertEquals('1', $asset->requestable);
diff --git a/tests/Feature/Assets/Api/UpdateAssetTest.php b/tests/Feature/Assets/Api/UpdateAssetTest.php
index 1eacab4fa7..80c63e1ac4 100644
--- a/tests/Feature/Assets/Api/UpdateAssetTest.php
+++ b/tests/Feature/Assets/Api/UpdateAssetTest.php
@@ -95,8 +95,7 @@ class UpdateAssetTest extends TestCase
         $this->assertTrue($updatedAsset->model->is($model));
         $this->assertEquals('A New Asset', $updatedAsset->name);
         $this->assertEquals('Some notes', $updatedAsset->notes);
-        // See StoreAssetTest for why order_number is no longer on the
-        // parent Asset column.
+        $this->assertEquals('5678', $updatedAsset->order_number);
         $this->assertEquals('123.45', $updatedAsset->purchase_cost);
         $this->assertTrue($updatedAsset->purchase_date->is('2023-09-02'));
         $this->assertEquals('1', $updatedAsset->requestable);
diff --git a/tests/Feature/Assets/AssetObserverOrderTest.php b/tests/Feature/Assets/AssetObserverOrderTest.php
new file mode 100644
index 0000000000..1238b569f9
--- /dev/null
+++ b/tests/Feature/Assets/AssetObserverOrderTest.php
@@ -0,0 +1,102 @@
+<?php
+
+namespace Tests\Feature\Assets;
+
+use App\Models\Asset;
+use App\Models\Order;
+use App\Models\OrderItem;
+use App\Models\Supplier;
+use App\Models\User;
+use Tests\TestCase;
+
+/**
+ * AssetObserver::created writes a matching Order + OrderItem for every
+ * new asset regardless of how the asset arrived (web form, API, CSV
+ * importer). Dedupe semantics match the adjust-quantity flow: a
+ * populated order_number shares the Order row with same-tuple assets,
+ * a blank one gets its own Order per event.
+ */
+class AssetObserverOrderTest extends TestCase
+{
+    public function test_asset_create_with_order_number_writes_matching_order_and_order_item(): void
+    {
+        $actor = User::factory()->createAssets()->create();
+        $supplier = Supplier::factory()->create();
+
+        $asset = Asset::factory()->create([
+            'created_by' => $actor->id,
+            'company_id' => $actor->company_id,
+            'supplier_id' => $supplier->id,
+            'order_number' => 'PO-OBS-1',
+            'purchase_date' => '2026-04-01',
+            'purchase_cost' => 199.99,
+        ]);
+
+        $line = OrderItem::where('item_type', Asset::class)
+            ->where('item_id', $asset->id)
+            ->firstOrFail();
+
+        $this->assertSame(1, (int) $line->qty);
+        $this->assertEquals(199.99, (float) $line->price);
+
+        $order = Order::findOrFail($line->order_id);
+        $this->assertSame('PO-OBS-1', $order->order_number);
+        $this->assertSame($supplier->id, (int) $order->supplier_id);
+        $this->assertSame($actor->company_id, $order->company_id);
+        $this->assertSame('2026-04-01', $order->purchase_date->toDateString());
+    }
+
+    public function test_two_assets_with_same_order_tuple_share_one_order_row(): void
+    {
+        $actor = User::factory()->createAssets()->create();
+        $supplier = Supplier::factory()->create();
+
+        $shared = [
+            'created_by' => $actor->id,
+            'company_id' => $actor->company_id,
+            'supplier_id' => $supplier->id,
+            'order_number' => 'PO-OBS-SHARED',
+            'purchase_date' => '2026-04-02',
+        ];
+
+        $first = Asset::factory()->create($shared + ['purchase_cost' => 100]);
+        $second = Asset::factory()->create($shared + ['purchase_cost' => 200]);
+
+        $orders = Order::where('order_number', 'PO-OBS-SHARED')
+            ->where('supplier_id', $supplier->id)
+            ->where('company_id', $actor->company_id)
+            ->get();
+
+        $this->assertCount(1, $orders, 'Same (order_number, supplier, company) tuple must dedupe.');
+
+        $lineIds = OrderItem::where('item_type', Asset::class)
+            ->whereIn('item_id', [$first->id, $second->id])
+            ->pluck('order_id')
+            ->unique()
+            ->values();
+
+        $this->assertCount(1, $lineIds);
+        $this->assertSame($orders->first()->id, (int) $lineIds->first());
+    }
+
+    public function test_blank_order_number_creates_a_distinct_order_per_asset(): void
+    {
+        $actor = User::factory()->createAssets()->create();
+        $supplier = Supplier::factory()->create();
+        $ordersBefore = Order::count();
+
+        $shared = [
+            'created_by' => $actor->id,
+            'company_id' => $actor->company_id,
+            'supplier_id' => $supplier->id,
+            'order_number' => null,
+        ];
+
+        Asset::factory()->create($shared);
+        Asset::factory()->create($shared);
+
+        // Blank order_number = distinct transaction, so both assets get
+        // their own Order rows even though supplier + company match.
+        $this->assertSame($ordersBefore + 2, Order::count());
+    }
+}
diff --git a/tests/Feature/Components/Api/AdjustComponentQuantityApiTest.php b/tests/Feature/Components/Api/AdjustComponentQuantityApiTest.php
index a1f8fadab2..3c87421481 100644
--- a/tests/Feature/Components/Api/AdjustComponentQuantityApiTest.php
+++ b/tests/Feature/Components/Api/AdjustComponentQuantityApiTest.php
@@ -46,7 +46,7 @@ class AdjustComponentQuantityApiTest extends TestCase
             ->firstOrFail();
 
         $this->assertSame(3, (int) $log->quantity);
-        $this->assertSame('PO-CMP', \App\Models\Order::findOrFail($log->order_id)->order_number);
+        $this->assertSame('PO-CMP', $log->orderItem->order->order_number);
     }
 
     public function test_note_is_required()