I was bored one day and decided to browse around the pool setting files and found this option:
define('YAAMP_FEES_EXCHANGE', 2);
Basically, for pools that does the auto-exchange feature, the pool owner can set any exchange fee's they want. Some pool owners are more transparent and disclose it but I've seen some where they don't mention it at all.
So just wanted to let people know that there is also a backend exchange fee that goes into place on top of the pool mining fee.