RE: 447/20x Vegas game! (OK...I'll come clean)
Jeff:
I would probablynot adjust a pins type sight for 10 yard games. It's going to be too much of a PITA to readjust for 20 yard games with a pins type sight. Just MHO. I think your still getting the benefits of that 10 yard game without adjusting the sight for it, you now are getting more comfortable with pounding the middle out of that target and it's probably allowing you to have a more relaxed "soft" aim.
It doesn't surprise me you shot a bit low. Keep in mind, the angle from you to the target is probably much steeper at 10 yards and this can change quite a few things including your anchor point, etc. It's a bit unusual, but it's hard to tell without seeing you.
If you really want to get the bow dead on sighted in for 20 yards, this is an old field archery trick:
Take a piece of tape, and place it completely vertical (checking it with a level). Shoot at just that piece of tape, and adjust the sight until your hitting that tape every time at 20 yards, absolute middle of the tape on your good shots. Now repeat with a piece of tape that is perfectly horizontal, and adjust yourelevation till it's doing the same. You will get much more accurate results sighting in your bow this way when just shooting for and adjusting for one thing at a time, as compared to just aiming at a dot and trying to hit the middle.
Once your sighted in for one plane, and then sighted in for the other, recheck the first plane you sighted in for.
Edit - I also use this method for sighting in my 3D bow, for each individual pin. Obviously windage should be set after the first pin but I recheck with each individual pin as well to make 100% sure my centershot is on.