Bill,

I posted a piece in Protein Power on a similar subject titled "Lean Body weight" and was able to find out how BF% are estimated.

I was curious too. BF% are apparently only an estimate based on a significant sample of men any women where known body fat percentage, determined by density in water, is compared to general measurements.

This explains how the various measure can differ. You and I would be less fat as women! Do you like my new shoes?