Well, I'm not sure anyone confirmed how many chips were in it either. If they were running a full 8 chips @ 25GH/s, then it doesn't come close to 75%.
Technically, the number of chips is irrelevant; neither the bet nor BFL's order forms said that customers were ordering a certain number of chips. The units are specified purely by hashrate.
That would sure matter to the pre-order line up though, wouldn't it? btw, what is the lead time on extra wafers when your yield estimate goes to hell?