It helped to make the graph normal. Just look at the graph how it changed
https://gyazo.com/603e7e8a4db2e2f52d2989c306dc2240
But actually it didnt help - i still earning 15% less than WTM displays.
There is an other problem now. The graph displays 2.1-2.2k hashrate instead 2.56k.
It displays more real hashrate before i set static diff. So i dont understand anything now.