My point exactly you don't have players that are 10% cheaper you have 90% of taxes or money going out because this amount will not go back to a team so that it generates even more transfer possibilities but simply going out of the system.
when i think a player is worth is 500k for me, and i get ten percent of the bidding money back i would bid to 550k and be happy to spend 5 k less cause i have trouble to round such stuff exactly.
But now we have a free agent who start with a fair or high price, and now get intresting again i buy him and instead of 485k to a team there goes 450k into the nirvana ;)
Ok maybe when you are out of fund and can not spend all your money on him, it make an difference but honestly how you would react in a buissness when someone say this cost 300$ but i reduce the price for you for ten bucks. So you take all your money out of the pocket and it is 290$ and he won't sell it to you ;)