Customers that transact Orders to you via an EDI X12 850 often need
you to send certain, customer specific, fields back to them on
subsequent documents. This is often a requirement at both the header and
item levels of the order. A common example of a header field would be
the department number. It makes sense for the customer to have the
department number returned on subsequent documents but we don't have any
use for that number in our SAP system other than to store the details
and pass it to subsequent documents.