Explaining where the G/L Class code used at PO receipt is defaulted from.

When you create a purchase order (PO), the order entry program populates the G/L class code (GLPT) in the PO Detail file (F4311) with the G/L class code of the primary location for that item. However when you receive that PO, the receipt program uses the G/L class code from the location in which you receive the items to specify the DMAAIs (distribution manufacturing automatic accounting instructions). That same G/L class code is written to the match type-1 record in the PO Receiver file (F43121).