If I am reading your post correctly you are shooting it seems , a finger release with back tension. I do this myself. Yes it is common to have different impact points with the same release shot with two different methods. Practice the method that you will be shooting with and use that in your shot sequence. When you shoot with back tension, you are holding the bow with the shorter stronger muscles in your back and not the weaker longer muscles in your arms. Thus causing you hold steadier and push through your shot. With this method you would be putting pressure on a different part of the handle causing the bow to torque differently as posted on another response to this thread. After a while shooting with back tension becomes second nature. Good luck.