When "SAR as Bref"  is used in customer deviation codes (CDC's) as the landed cost reference, this means that the gross margin (GM) on the  customer orders (COA), shipping advice (CSA) and customer invoice (CIN) for the new replacement order items that are sent back after repair, are calculated based on which goods reception document (SSA) they are linked to.

If the customer deviation codes (CDC's) have "Copy from source", then the replacement delivery will get the gross margin (GM) from the original delivery and it is not certain that the cost on it is the same.

In this case there could be problems matching billing (GM) against stock (the cost of the item being taken out) and the result can be a deviation in the accounts.