I'm trying to help a friend with a problem he's having with his new Mission bow. Every few arrows...the arrow would impact either very high or very low in the target....no left or right flight problems. When we paper tested the bow, the tear in the paper woud consistently be nock low...the tip would penetrate the paper and the tear would go downward with the nock exiting 3 or 4 inches below the tip entry point. We tried moving the nocking point on the string up and down without any change in the tear. Shot different stiffness arrows...with no change. This is a two cam bow and I was wondering if it could be a cam timing issue. If anyone could help, it would be much appreciated.