I'm not sure why your two scales are different, but the hanging scale will only measure the draw weight of the bow. All the weight of the bow will do is start to draw the sting back when you hang it on the scale. If your bow weighs 5 lb and you hang it on the scale by the string, the string will have 5 lb of draw force acting on it.

All that really matters is that you can hit what your aiming at. Good luck

Jaybird