Are you shooting TIGHT groupings???? If not, I'm inclined to agree with the rest of the group as the problem is likely FORM. If you are, don't mess with paper, screw on some BH's, make sure they spin TRUE, and BH tune the bow, a BH tune will tell you a lot about what's going on......"strings stretched causing nocking point to have changed,".........."rest maybe ain't as 'centered' as you thought,"........."If they are all over the place, your form is a bit inconsistant."

Also, did you by any chance crank the poundage up on the bow?????? If so, you're arrows' spine may not be accurate. If you are using and open hand grip, gently lock out your bow arm at the elbw, so that you have a more consistent anchor, and see what that does.