It seems Po_lines_interface.Action can be set as 'UPDATE' to add a new line in the shipment. It is doable to add a 'Price Break' to a 'Quotation' etc.
Consider a PO, with 1 or more lines. Each line has 1 or more shipments on it already. is there any way to add one more additional shipment line to an existing shipment line. I want to do this for 'Standard' POs.
Seems both PO header and line tables have this 'Action' column. Played a bunch with the combinations but it didn;t work.