ah i see.. we have three sepparate things we should not mix
1.
the purple graph shows the balance i definitely will get from the pool.
the green graphs shows the balance i could get someday with luck
the blue graph tells me, what value the purple graph would take, if a block would be found at that very moment.
2.
we have a CPPSRB payout scheme.. every rewarded share goes to the purple "unpaid balance" and every not yet rewarded share goes to the green "maximum reward". here we use LIFO: every time we have luck > 100%, old shares are digged out of the share log and get "rewarded shares"
Correct.
3.
we have a sliding window of 6-7 blocks, called payment queue: every rewarded share will be paid out. maybe not in the actual block, but at latest in 6 blocks. the priority here goes with payment ages. this structure is recalculated from time to time.
the last question for me: why do we have this windows of 7 blocks? i guess it might gain 25 BTC everytime a block gets orpahned? but how can it get smaller?
Each time a block is found by the pool, one of two things happens.
Normally the block contains payouts to miners directly in the coinbase transaction. In the case, the payout queue remains at relatively the same state (doesn't increase in size) and is normal operation since the payout queue contains estimated payout for the current round.
Sometimes things cause the pool to not have a definite payout list available to include in the coinbase transaction for one reason or another. Generally this happens when the pool finds a block very quickly after another pool or miner finds a block and Eligius hasn't had time to build a block template that includes the full coinbase transaction yet. Historically this is only a few % of blocks. When this happens, the payout queue will grow by the value of that block's reward since the shares for that block have been rewarded to miners, but no payout based on that block's reward has been made yet. Since it wasn't able to pay miners directly immediately, it pays Eligius's offline wallet and I use those funds to pay towards the payout queue once the block fully confirms and I have time to get the funds out of offline storage. When that happens (manual payout) miners get paid and the payout queue gets reduced by the amount of the manual payout, generally back down to 1 block (the current round's estimates).
Orphaned/stale blocks don't affect the payout queue because they essentially just never happened in the eyes of the reward system (shares rewarded by a block that becomes stale/orphaned are simply unrewarded).