P2Pool?

Greetings everyone once again!
So Ive been mining now for almost 2 months. I ran into some issues with P2Pool seeming to lose shares. From what I understand, it actually never lost the shares, but when I have to restart my machine, the p2pool.exe will only show shares that have accumulated since it's start. I'm still confused as to why the payout amount changes though. Sometimes it will show a payout amount of, for example, 0.01, then drop to something like 0.008. If anyone knows why that is, any advice would be greatly appreciated. Anyways, after a couple weeks on P2Pool the apparent share loss thing was bugging me so I went to BTCGuild for a while, and they seemed to provide a lit more stability, albeit at a lot slower mining rate. I stayed there for a bit, but wanted to go back to P2Pool and give it a shot since they payout seems to be larger. I've been back on P2Pool for about a week, and things seem the same, that is the value will climb, then drop. Also, when I was in that first couple of trial weeks, I got a payment of 0.13 BTC which is the best I have gotten so far, but I am confused as to where that came from. (None of the payout amounts reported were anywhere near that). Is there something going on where I get a payment as later blocks are found? Is there something like a bonus as the work progresses, or a separate weekly payout, that is somehow purging those shares and rate drops I see into a payment at a later time? I'm pretty confused by this so any advice is greatly appreciated.
Also, since I've been back, the block time has increased dramatically. I've been going 7 days now, and the first block took over 5 days. We're already into 2d 12h on this new block. Is something going on to cause such a huge jump in time that I don't know about, or is P2Pool just experiencing a run of bad luck? Thank you all~!

Don't know if it matters, but I'm using p2pool.exe windows binary, cgminer, and an HD7770.