p2pools just arent that transparent. they don't show orphaned blocks in stats. you'll be surprised to see how much orphans there are for real. and this is a common situation when hashrate skyrockets like 2x from it was before on a same difficulty. that means there are like 8 blocks per minute instead of 4 blocks expected.
and guess who's guilty? pool hoppers! they pop out when diff raise and pop back in when it goes down, making hashrate go up and down like crazy thus making network less stable. and then they're whining like why don't we get those coins that calculator shows? :E
actually there was the same profit when diffuculty raised and hoppers gone out. we got less orphans thus making us digging same amount of coins with higher difficulty, lol.