Hi, I'm using claymore v11 since about 2 weeks in dual mining mode ETH + BLAKE2S with Ethermine pools for ETH and Nicehash for BLAKE2S.
After the 1st payment my Nicehash "profitability" has dropped (from 0.0005-6 BTC/day to 0.0001 BTC/day)... Gh/s and difficulty are the same...Do you have similar experiences? thank you

You should never mine at nicehash unless you are okay with their payments, is always 40% - 150% less than you would receive mining on a proper pool. I did some tests just to check the earnings on nicehash, I was supposed to earn $8 on a proper pool and nicehash paid $3.40, that is just an example.