Nicely done, but there is NO explanation WHY it is 10% longer than it "should"

And I have absolutely no idea if it is even possible or how.
I have a idea, but unsure how to prove it.
In my case P2pool.info ALWAYS and sometimes even my local node shows more hash rate than I have on my miner.
Maybe it it all ok in pool itself, just numbers send/taken to analysis are screwd? By this magic 10% ?