What am I missing here?

I assume there may be several factors that might affect this but why is winminers estimated revenue(not profit) much less than say whattomine?

I use 6x 570 and the discrepancy is about $7/day mining PIRL for example.

I genuinely want to know so please constructive feedback as to why it's so. i;m not after suggestions like mine direct with pool etc etc.

@TeamWinminer can you shed some light on this?