Verify the actual scope
Compare participants, products, duration and complete terms. Similar naming does not guarantee the same calculation basis.
A changed threshold or discount-combination rule can affect cost despite an apparently identical rate. Retain the applicable versions rather than using only today's campaign description.
Identify external changes
Seasonality, availability and an unusually large order can affect sales independently of the promotion. State known circumstances instead of assigning the entire difference to one cause.
Check settlement completeness too. A result with open costs is not equivalent to one after closure.
Compare components, not one amount
Turnover, volume, mix and condition costs show different aspects. Together they support investigation without proving a particular action caused the outcome.
For a CFO, distinguish a changed economic result from changed data scope. Trade Marketing retains campaigns and calculations. Comparison becomes useful when differences remain visible instead of being concealed by one shared promotional name, giving the team a clear basis for deciding which assumptions need another check.