diff --git a/src/DataTransferObjects/Requests/FulfillmentInbound/CreateInboundShipmentPlanRequest.php b/src/DataTransferObjects/Requests/FulfillmentInbound/CreateInboundShipmentPlanRequest.php
index ec309ba3..72fd076e 100644
--- a/src/DataTransferObjects/Requests/FulfillmentInbound/CreateInboundShipmentPlanRequest.php
+++ b/src/DataTransferObjects/Requests/FulfillmentInbound/CreateInboundShipmentPlanRequest.php
@@ -3,8 +3,11 @@
 namespace Jasara\AmznSPA\DataTransferObjects\Requests\FulfillmentInbound;
 
 use Jasara\AmznSPA\DataTransferObjects\Schemas\AddressSchema;
+use Jasara\AmznSPA\DataTransferObjects\Schemas\FulfillmentInbound\InboundShipmentPlanRequestItemSchema;
 use Jasara\AmznSPA\DataTransferObjects\Validators\MaxLengthValidator;
 use Jasara\AmznSPA\DataTransferObjects\Validators\StringEnumValidator;
+use Spatie\DataTransferObject\Attributes\CastWith;
+use Spatie\DataTransferObject\Casters\ArrayCaster;
 use Spatie\DataTransferObject\DataTransferObject;
 
 class CreateInboundShipmentPlanRequest extends DataTransferObject
@@ -19,5 +22,6 @@ class CreateInboundShipmentPlanRequest extends DataTransferObject
 
     public ?string $ship_to_country_subdivision_code;
 
+    #[CastWith(ArrayCaster::class, itemType: InboundShipmentPlanRequestItemSchema::class)]
     public $inbound_shipment_plan_request_items;
 }
diff --git a/src/DataTransferObjects/Responses/FulfillmentInbound/GetTransportDetailsResponse.php b/src/DataTransferObjects/Responses/FulfillmentInbound/GetTransportDetailsResponse.php
index baf74830..64c03b31 100644
--- a/src/DataTransferObjects/Responses/FulfillmentInbound/GetTransportDetailsResponse.php
+++ b/src/DataTransferObjects/Responses/FulfillmentInbound/GetTransportDetailsResponse.php
@@ -7,5 +7,5 @@
 
 class GetTransportDetailsResponse extends BaseResponse
 {
-    public GetTransportDetailsResultSchema $payload;
+    public ?GetTransportDetailsResultSchema $payload;
 }
diff --git a/src/DataTransferObjects/Schemas/FulfillmentInbound/InboundShipmentPlanRequestItemListSchema.php b/src/DataTransferObjects/Schemas/FulfillmentInbound/InboundShipmentPlanRequestItemListSchema.php
new file mode 100644
index 00000000..eca4b232
--- /dev/null
+++ b/src/DataTransferObjects/Schemas/FulfillmentInbound/InboundShipmentPlanRequestItemListSchema.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace Jasara\AmznSPA\DataTransferObjects\Schemas\FulfillmentInbound;
+
+use Illuminate\Support\Collection;
+
+class InboundShipmentPlanRequestItemListSchema extends Collection
+{
+    /**
+     * @codeCoverageIgnore
+     */
+    public function offsetGet($key): InboundShipmentPlanRequestItemSchema
+    {
+        return parent::offsetGet($key);
+    }
+}