I had the same problem when i first put my WB on a couple of weeks ago. First of all, I paper tuned the rest as best as i could. Then I shot right on at 20, but was shooting about a foot left at 40. I moved my rest a little to the right and kept playing with it until I was shooting the same at 20 and 40. this will take some trial and error. You don't necessarily have to be hitting where your aiming, as long as your hitting the same distance off at both 20 and 40. Then you can adjust your sights accordingly.