The case may arise where you have sold a procured product before the PO has been costed with a different cost than shows on the receipt. The line on the Receipt will have a sold icon at the far right.
You will need to click on the sold icon to unlock the line item. This will allow you to make a change to the receipt/PO cost for that line item. Make sure any cost changes are saved. This will update the COGS and Inventory values on the affected order(s).
Note: if the receipt is for a purchase order generated from a work order then you will not be able to make changes to the line item cost on the receipt. You will be required to cancel the sales invoice and the delivery, update the cost, and then recreate the delivery and sales invoice.