The truth is a broadhead from a decent bow will more than likely blow right through the actual shoulder blade (it's pretty thin like a ribactually except for a ridge that runs about 2/3 up the blade). The problem I have seen is that the shoulder blade itself is attached to some serious bone. If you are off by an inch or 2 you could hit the shoulder socket itself and I don't care what you are shooting in terms of lbs draw and what brand of broadhead but if you hit a deer right on the point of the shoulder it isn't making it through the deer.

Save the shoulder shots for the guns, they are designed to drop animals this way. With a bow you are trying to slice through as much vital material as possible and that is located behind the shoulder. One of the big things for a guy picking up the bow from gun hunting is learning to pass onthe quartering towards shot and hold off for the broadside or quartering away shot.

After you have shota few and seen how that broadhead works inside the deer you'll see why you want to avoid the shoulder.