Not sure what exact numbers did you get into account, it's not clear from your post. Which payouts, for which miner, in which time frame?
Something that you probably didn't take into account, that you're also accumulating Immature and Unexchanged coins for each miner. These are accumulated throughout all miners and takes a significant percentage. With this in mind you'll get paid just the same of direct Ethereum mining, but with some delay due to Immature and Unexchanged coins buffer.
No, quite the contrary, NiceHash is the best paying no-hassle auto-payout multi-algorithm service out there.
Best regards,
NiceHash team.