Statistics
https://whattomine.com/ says that with 29 mx profit is equal to 1.04 dollars, without paying for electricity.
Pool payouts statistics
https://ethermine.org/ shows a profit of $ 0.74 with 29 mx, without paying for electricity.
steil shares 2%
Why is this happening?
Right now I am not mining ETH but, last time I mined ETH the profits were close to what whattomine was saying. Change of 30% is huge if you ask me. Maybe try re-directing the hashpower to a different pool and check if there is still some discrepancy.