ORIGINAL: LBR
Get more practice. Could be a form error, could be a focus problem. Don't worry about 20 yds right now--get your form down, work on your focus.
I don't step off or measure yardage--that might help also.
Chad
Yep, practice allot more! Another thing to like LBR mentioned it could be form. To me it sounds more like a form problem or maybe a bad release. With these Traditional bows your holding 100% of the weight on your fingers so the farther out you shoot the more its going to show with a bad release (more time for the arrow to move in either direction shooting longer distances). Usually thats the case with me when I extend my yardage when practicing and when I start missing bad its usually my release causing most of the problems.