The Behmor roaster doesn’t have user adjustability on the fly as others do. You are stuck at custom build-in profiles. The body of in the coffee is developed between 1. and 2. crack, so extending the time between the cracks is essential.
A great tip I saw at http://evadeflow.com/2011/10/behmor-baked-beans/ lets you have a little more control over when the heating element is on at full power and at 30%, thus extending the roast. The tip is basically that you preheat the roaster, load in about 200-300 gr of coffee and choose the p2 one pound setting. Then maximize the time and start the roast. When you are near the first crack turn off the lights and watch the heating element, then slowly reduce the time until the heating element does off. When the heating element is of you now that you have reached the 30% power of the profile. Doing this and opening the door shortly will help you to extent the time between first and second crack and achieving more body in your coffee.