Calorie Estimation, BMR and Exercise

I think the trickiest part of this app is getting the BMR right--are you sedentary, moderately active or very active? I have a desk job and I set my BMR at sedentary, but from previous weight training and working out I suspect I have a slightly higher BMR from muscle.

And the other tricky part is estimating calories from exercise. If you walk at a snail's pace on the elliptical with little resistance, I guarantee you are not burning 10 calories/minute.

I set the app to lose 1.5 pounds per week and am down about 6 pounds over two weeks. Then again, some calculations may be off. But I will take it as long as it doesn't go over 2 pounds a week--don't want to lose muscle.
-Chris