600 CFM vs 750 CFM...

Always remember the WB is a tuning tool. The numbers aren't set in stone. There are some really good threads over on speed talk about WB tuning and how the WB can produce different numbers.

Tune for best performance. Then check your numbers. I'd bet money your tune is better than 95% of the stuff out there.

Don't get buried in the numbers or the minutia.

As an example, if you run enough compression and enough cam, you'll never get your WB idle numbers as lean as some guys do, or claim to do.