Check to see if your nocking points are in the same spot. If your nocking point is higher , the arrow will oscelate more coming out of the bow. Even 1/8 in differance can make all the difference in the world. You could still shoot groups with the nock point being a little high. But will usually have a little more noise and you could also have trouble getting a fine tune on paper or bareshaft. The arrow rest will have to move along with the nock point if you find it high to maintain your square. Or it could be what the other guys have said, They are all good points. Good luck.