Bodymedia Fit and sleep.

listabit

I got my BMF a couple weeks ago and am amazed at the sleep tracking results. It seems I don't sleep very well. The most sleep efficient I have been in 80%, and that was only once. I'm "laying down" plenty of hours 8-9, but only "sleeping" 6 or so. What do you all think about this measure? How has yours looked? Anyone have a sleep efficiency over 80%?

I don't know how it is measuring the sleep v. laying down. I always thought I was a good sleeper, but then again I do walk around tired alot.

Thoughts?