Editing the source of a product on an order after the fee slip has been recorded, does not reduce the inventory quantity on hand for that product. For example, if you edit an order by changing the source of a frame from "From Vendor" to "Enclosed from Location," that frame that you are pulling off your board to send to the lab is not deducted from your inventory counts.
If you must change the source of a product after the order and fee slip have been recorded, void the fee slip and delete the order, create a new order, and record a new fee slip.