I'm stubborn and don't really want to switch pools rn, but I will after my next payout.
However my daily earning has increased on Dwarfpool since I switched the developer fee off (funny enough by about 2-3%) which, to me, is almost enough evidence to support my claim. I'd need a longer run of time to be more confident about those results tho.
I checked my logs and everything and "nofee 1" actually produces less shares than devmining enabled. So its actually is hashing slower.