I have been asking various friends about that too. It doesn't seem to correlate to age, so I guess just fitness level? It is just totally weirding me out that I was an 18/20 at 210 and I am an 18/20 at 260-ish. Totally, totally, totally weird! And HOW did I put on 50 lbs of muscle? I haven't been consistently active. But hey, I ain't complaining.