So unfortunately just ran into this issue myself. The BO for CustShip is retarded and wants you to send it exactly 1 ShipDtl record not the WHOLE ShipDtl (multiple lines)
So when you do GetNewShipDtl ()
you need to basically build a separate dataset (or clear out the old one) to make the subsequent calls.
I’m looking to see where the issue is is one or two of the calls that don’t want multiple lines.