Std Invoice cannot be applied to prepayment matched to PO if matched line number is different

Summary:

There seems to be validation at PO line level when trying to apply an invoice to a prepayment which was matched to a different line.

From the documentation:

"Yes, and the invoice that you apply the prepayment to must have at least one line matched to the same purchase order as the prepayment"

According to this, the PO line number matched on the standard invoice should not matter, as long as PO Number is the same as the PO Number on the mathced prepayment. I.e. validation is at PO Header Level.

This does not seem the case.

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