there really is no reason at all to play pp once you have 20 mil def and 20 mil off, unless you want points. or have 150k in lights and heavies to burn off. the only point is for a conversion of weak troops to large troops. also if you have precise attacks you can stretch your troops out as far as possible. a calculator is the only way to do this, if you are not using a calculator you are wasting your troop units. so think about what the point is of PP and know the rewards are capped.
my noramal payouts are 20 mil in def the highest I usually see is 34 mil. for off the usual payouts are 15-20 mil the highest I get are 54mil.
if anyone has better payouts I would like to see them!!! seriously.
the bank is one total bank. so don't expect large payouts on low levels levels are 1-170. so the higher you play the bigger the reward. stay in the same range of positions and this will happen. if you lose your army with no rewards wait until you can knock down one more position in that range don't play lower ones until you get your payout.
also if you don't have 100k or more in lights and heavies or at least 20 mil in phalanx and cav, you will not get big payout. but that is the reason there is no reason to play them, what you put into them you get back out of them. it is an upgrade in units not a bigger army. which makes this aspect silly.
and think about this if you are only gonna get a certain amount of power once you get it no reason to play again as it will cost you 24 mil + for next payout.