new scales- %s?

I bought some new scales, and tried them out for the first time this morning. I splurged a bit and they do % water weight, body fat % and muscle as well.

I'm not sure if I'm just being stupid, but shouldn't all these %s equal 100? The weight seemed roughly what I was expecting, but it said 60% lean muscle, 17.7% body fat, and 70% water... I know muscle has water in it, but that much? :S