However that 91.4-91.6% luck absolutely does not describe a miner that has had a stable hashrate and been mining continuously for a year on this pool.
my hashrate has varied a bit here
Well, this is a bit self-contradictory...
Umm no. In order to be worse it would have to vary more than mine which has varied a little but not a lot (sometimes miners stop hashing, sometimes the internet goes down). Ergo, a number worse than 94% indicates someone who was mining less consistently than me.
Regardless OrganOfCorti already made the same point using the maths.