your bow must be going pretty slow if their is that much of a gapfrom 15-25. i have a 35 yard pin and at 45 and 50 yards i have to guess a little on where it is going to hit but i know how high i have to aim for it to hit it's mark. so figure out how high you have to aim your 15 yard pin to be on at 20 yards but i just can't see how 5 yards can make that big of a difference.

also i think it would be easier to sight your bow in from the ground then move up into your stand and tweak the pins if you need to