GL Offset overridden in P4310; defaults back during receipt (P4312/F43121)

I have an item that I purchase from an internally related company 90% of the time, and I want to route it to a holding account using DMAAI 4320 at PO Receipt.  The other 10% of the time, I purchase the item from an external vendor, and I want to route it to my regular RNV account at receipt. 

I have set the GL Class Code on the Item Location Revisions to IC10 (Raw Material - Related Co), which defaults into the PO.  I can override this GL Class on the PO to IN10 (Raw Material - External Vendor).  However, at PO Receipt in P4312, the GL Class code defaults back to IC10, and does not display anywhere to be changed.  It is only visible in F43121 after receipt.