...and the calculations done on a form - where each of 3 textboxes displays the commission calculated based on the commission percentages per salesman. I think it would be easier than doing so in a query, as long as you don't expect to be creating new commission types. IIF's are out of the question. For each new or additional salesman, all query expressions would have to be re-written, and would only get more complex.
Also, this may be one of the "rare" cases where it's ok to store calculations in a table.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.