Reply #1: They don't know how much because . . .

[gratuitous]

Knowing how much makes it easier to set the amount of damages. I think they're on the hook for $4,300 per barrel for every barrel that leaks out. So if nobody knows (and you damn betcha they know and count every drop that comes out of a properly functioning well), then you have to estimate, and the estimate will almost certainly be low, especially since BP has been low-balling the amount for seven weeks.

Also, notice how, when we're talking about how much is supposedly being captured, BP lurves to talk about the number of gallons (big number), but when we're talking about how much is spewing, BP would prefer to measure it in the much larger barrel (so the number is smaller)? And with a society as mathematically illiterate as ours is, I'd bet that this is no coincidence.