Each mechanism has a different basis
A discount changes a price under agreed rules. Free goods still have a cost even when the customer does not pay separately. A bonus may depend on turnover, quantity or purchasing mix over a period.
Combining the mechanisms into one amount makes its origin difficult to check, especially when some costs are immediate and others are settled later.
Record the condition and calculation timing
Identify the relevant customers, products, period and calculation basis for each element. Define treatment of adjustments and interaction with other campaigns too.
Do not assume all percentages can simply be added. Their sequence and basis may affect the result, so these must follow the agreement rather than the habits of whoever maintains the spreadsheet.
One report does not require one input field
Costs can be presented together while retaining their separate origins. This makes both the total and each mechanism verifiable.
For accounting and analytics teams, the distinction supports an understandable calculation. It does not replace accounting policies or interpretation of an agreement. Trade Marketing organises terms and data so that the result does not depend on guessing what one combined figure contains.