We purchase and sell Inventory A and Inventory B. Sometimes, when inventory B is not available, we deliver it to Contractor A which modified it to become Inventory A (or vice versa). The contractor bills us for the service. How is this best accomplished in NS? What I can think of is to create a PO for the cost of service and use the inventory that will be delivered to us. Process normally. Then, create inventory adjustment to transfer the cost of inventory from Inventory A to B or vice versa. However, we have the same inventory account that is not allowed to be used as Adjustment account. That's why we may need to post it first to a holding account then do a JE to transfer it to the inventory account which is ugly. We are using FIFO method.