rakeback on Ultimate?

[emerson]

I am fairly new to Ultimate. I got there via the thisisthenuts site, which claims to pay 30% rake back. Each day I check the Poker Tracker stats to see how much rake I paid. Then I check the rake back site to see how much I got. It appears that the actual amount of rake back given is 17% to 18%, and not anywhere near 30%. Is this a mistake on my part? Has anyone else noticed this.