My WU are 820/750/710
2.5MH in total
6.5% reject
2.1MH shown at site :/
learn the math

u got 2280 in total not 2.5.
2280 - 6.5% rejeccted x 2280 = 2131.8 = 2.1Mh/s.
It ok now?
Learn read

WU is 2280. Hashrate is 2500
But you're right. The calculation seems to be based on WU not hashrate. But why is it so low at clevermine?

I think the coins are switching too fast. Network diff is jumping up and down twice a minute.