Or what's happening with the 'expected payout' it hasn't increased in sometime now...
Can I buy a Vowel or a Clue as to what's going on?
The expected payout is what you can expect to receive when p2pool hits a block. It won't change much unless your % of the pool's hashrate changes.
The only place I find the word "expected" is on the
NastyPoP payout rates page. That page shows only past payouts. The "vs. expected" column is based on math calculation of hashrate and compares past actual payouts against what a miner could mathematically expect from mining hardware at that time.
The P2Pool hashrate is low these days. From this we see big variance. Maybe 10 weeks of near 0% payouts and then a week with 1500% payouts. NastyPoP miners also receive parts of donations to nastyfans. That is why some weeks have >0% payouts even when P2Pool did not find a block.
Hints about payout when P2Pool finds a block is in "current P2Pool mining round" table of the
NastyPoP Ticker page. These values base on the collective hashrate of NastyPoP against collective P2Pool hashrate. A list of all P2Pool miners with payouts for current P2Pool round is available
here. NastyPoP mines as 1NastyBTCcxbAQQ22kEijbXqgyBPRujftL.