i realize i didn't account for difficulty. i wasn't exactly sure how or if it was applicable. there were 2 difficulties in my data and it went down by only 83000 when it changed; a pretty small amount compared to most of the other difficulty changes i've seen. small enough i thought to not really have an effect on how it would impact results if it was applicable. is that a poor assumption?
why exactly does difficulty need to be applied at all? how does it change the ratio of my actual earned BTC/day/Ghash/s to somone's BTC/day/Ghash/s who mines at a PPS pool?
Fee-free PPS reward for mining 1Ghps for one day at current difficulty = 10^9*3600*24*50/1777774/2^32 = 0.5657797
Fee-free PPS reward for mining 1Ghps for one day at last difficulty = 10^9*3600*24*50/1805700/2^32 = 0.5570296
Yep, not a huge increase - only about 1.5%. But if you were looking at several months, especially when difficulty was doubling, it would have a rather large effect.
For the record, my average
weekly oops, daily reward at 1Ghps is about the same as yours atm, about 0.85.