The calorie burns include your BMR - the calories you burn existing. I've burned about 500 when I'm up at 6 am, too. The steps is associated from movement in your sleep, it's an imperfect system that doesn't actually go off of steps but the movement of your arm. I'm guessing your initial 1200 calorie burn was because it was the middle of the day. That being said, I found leaving the HR function running gave me grossly inflated daily burns so after the first week I turned it off and only turn it on if I am doing intentional cardio. It's been more inline with previous calculations and expected losses.