If the calculations are right then that seems like a suspiciously round number, doesn't it. Do you think that have they decided that 40% is a perfectly sustainable commission rate but only as long as they cull the herd down from whatever-thousand contributors they have now, to this "golden 100" of top performers?
No, it's not a 'suspiciously round number' at all. I'd say that is
exactly what they would have done. If you want to increase profitability by cutting commissions, but also want to limit the damage to your future business by taking care of your top suppliers, the first thing you need to do is to work out how many suppliers you will allow into that category. The 'Top 100' seems a reasonable enough number __ certainly more so than say the 'Top 371' which is the sort of figure some folk have mooted.
Only once you have decided on the 'framework' can you work out how much each lessor category needs to lose in order to achieve the target. The more people they allow into the top tier, the more everyone else has to lose out.