I think it's when Pete came out w/ BBeast v1.0. And CM came out w/ 5.0.7, that wiping once just wasn't taking. Most of us had trouble installing these ROMs unless we wiped 3x. I have no idea why, I don't know the particulars like you guys, but I know I couldn't get my ROM to run right (if at all), if I didn't. It was only for like those ROMs, though.
"How many bloody Gs are there?"