Actually, if you look at where I drew the line to demonstrate, how the pocket, that most hunters aim for ,right behind the shoulder, runs up the deers side ,you will see if you aim midway up the body, you are probably aiming where I drew in light blue, therefore a slightly foward hit, for the same distance, will just as likely hit bone, as aiming slightly lower, maybe even more so, since the scapula is bigger than the leg bone.

Just for reference. This is a deer I shot in 07'. I was aiming low for the heart and it hit slightly higher, since it was only a 10yd shot and my bow is sighted for 20yds. The broadhead broke the scapula and took out the heart and both lungs.