I switched the failover sequence of my merged minings pools to put bitparking's mmpool first instead of my own p2pool, and boom, I am now seeing 3.35 terrahashes on the LCD readout. So somehow p2pool was causing me to lose 2/3 of my hashing power.

I tried removing geistgeld, the fastest block time merged mined coin, such fast blocks that mmpool does not merge them, from my merge but still as soon as I switched back to using the p2pool pool the hash rate shown on the LCD started dropping back down again.

So I guess it must be something about my p2pool, rather than the fact that I merge more coins with it than mmpool does, that is causing such massive losses.

-MarkM-