Major difference is:
ckpool - SPLNS vs kanopool - PPLNS
SPLNS has the characteristic of larger miners subsidizing lucky small miners (shares are not created equal)
PPLNS delays payout for each share across 5Nd: each share you submit will - on average - payout 100% across 5Nd; more if pool is lucky for 5Nd and finds more than 5 blocks, less if pool is unlucky and finds less than 5 blocks.
Our 5Nd is currently around 8 days ... theirs is ... stretching off to the horizon
However, also, there's the issue that until a pool gets big enough, you are losing a lot to diff changes.
Of course there's nothing to be done about that ... except make the pool bigger ... which we've been doing well since the drop last year
Twice we've dropped due to poor luck, and made a recovery - unfortunately there's nothing to be done about the luck though.
It goes up and down - that's the nature of the beast.
Looking at the long term statistics, we're pretty much right on target though.
February's numbers (or worse) are actually expected, on average, about once every 500 blocks, which is what the CDF[Erl] value says.
But the effect is obviously greater when the pool is only around 50PH (or worse if it's smaller)
But we must continue to grow, and people keep joining so that's working well