Admittedly, it's an anomaly that it transfers the external document no. but not the shipping agent/service. It should either do none of them or all of them so that it is consistent.

But there are users out there who do not have a one-to-one relationship between sales orders & shipments - it depends on the kind of business you are in. I know a number of instances where a warehouse shipment is a collection of deliveries that a van driver will do in one day, so there are multiple sales orders on each one for different customers. I can see where people are coming from with this request but any amendment should not restrict the one-to-many use case.