Hi Jurgen,
I agree with you. However, our management decides to centralize all deliveries of PO to our central warehouse which is Plant B (performs GR 105). Then it will be Plant B's responsibility to transfer (303) the requirements of Plant A in another island. In this case, traceability is easy for each line item from the time it was delivered, transfer (in-transit) and GR by Plant A.
Regards.