Does yiimp's earning estimation match that of the exchanges? It should be trivial to check if you have access to the DB, and it'll probably help locating where things go haywire.
there's no question about exchanges and estimates anymore.
you mine a coin with payout to same coin on a single coin pool and it takes 20% (or more).
i doubt the op needs any help here

Aaaah, true. Didn't think about that. I've been absent from this thread for too long