So, is anyone else getting low payments from "communitypool.stellite.cash" ?

According to several calculators compared to payments from pool i'm getting roughly 25% less than i am supposed to.
Got a stable hashrate of 28 KH/s (2 rigs) and tried both static diff and dynamic but same result. At worst i got about 1% invalid shares but this should not ammount to 25% less profit.

each rig has an avg. result time of approx. 30 sec on diff 400k.

Any suggestions?