Wanessa,
From my understanding, in standard SAP SD, there is no material determination at shipment level. It is only at sales document level (or material determination procedure is assigned to sales document type).
Few observations, in IMG path -
1. Transporation>Basic Transportation Functions>....
There is no material determination!
2. Logistics Execution>Shipping>Basic Shipping Functions>Material Determination
But there too the material determination procedure is assigned to sales document type (and not assigned to the delivery type). Wonder why this information is then given in LE part (too)?!
Your company wants to change / substitute material at shipment level.
Why?
User wants to change the component of a BOM, at shipment level.
That mean this component information would be something else in the sales order and delivery (as compared with this component information is Shipment). Correct?