The system uses the document type to decide what data in the sales document to use for determining substitute products. The link between procedure and document type directs the system to the selection records that are processed during order entry.

By making this assignment, you are essentially "turning on" substitution for specific document types. If you do not make an assignment, the system does not check for substitutes even if the records exist.

To assign a product selection determination procedure to document types, perform the Customizing activity Basic Functions ® Material Determination ® Assign procedures to sales document types (transaction OV14).