Establish the link with the original transaction
Connect the return with the product, customer and sale concerned. A shared product name is insufficient where purchases span several campaigns or periods.
Distinguish when the adjustment arrived from the period of the original event. Their effect on the bonus should follow the agreed terms.
Adjustments do not all have the same effect
Quantity, price and product-allocation changes can affect different conditions. For a mix-dependent bonus, the total value is not the only relevant figure.
Define what happens once an earlier result has been communicated. Silently overwriting the amount makes its change difficult to explain.
Keep the version and recalculation reason
Retain the previous outcome, new data and applied rule so reviewers do not have to reconstruct events from several files.
This is particularly important to accounting and analytics teams. Trade Marketing organises the calculation without replacing interpretation of the specific agreement. Define adjustment treatment before settlement rather than reopening the calculation principles whenever a later return appears.