Where did I assume G80 uses all 225W? The only thing I assumed is that the power connectors rumored to be on R600 wouldn't let it exceed 225W. G80 uses ~170W, allow 15W padding with the 225W max and R600 can't be more than ~40W more. Where was I messing up with that math?
The r600 might not use the full 225 watts but probably pretty close to it, if overclocking needs extra power