Asset Source Lines: Why is Invoice Number field populated by PO Receipt Number

Our current process in summary: we capture a Requisition, auto-create a PO (i.e. PO: 1000781), receive the PO (i.e. Receipt: 2000314), send information to Projects, send asset lines to Oracle Assets, Post Mass Additions, view asset (i.e. Asset: 9138) Source Lines in Oracle Asset - the Invoice Number field is populated by the PO Receipt Number (Receipt: 2000314), capture AP Invoice (i.e. Invoice: INV1000781) and match to PO (PO: 1000781), validate AP Invoice.

The reason for capturing the AP invoice at that point is all the necessary concurrent processes are listed in a Request Set and is scheduled to run once a day. The asset number is generated in Oracle Assets before the AP Invoice is received from the Supplier.