I've shot split fingered with middle finger anchored in the corner of my mouth since I was a kid. I've recently started shooting again and have been plagued by a "hitting left" issue about 50% of the time. I know that I've ruled out every possible tuning issue...then I tried shooting 3 under for a few weeks, but that wasn't going to do it for me anywhere but on the backyard range.
Terry looked at a couple of videos my wife took and made some solid suggestions about back tension and bow arm control that I've been working on, but I was still looking for that final piece of the puzzle that would close up my groups.
So today I changed my anchor point to where the middle finger anchors on my cheekbone almost directly under my eye.....Bingo! Solid, repeatable anchor position that has resulted in much tighter groups, shorter Point On distance, and solved the hitting left issues.
Just thought I'd share my solution to my own puzzle....your mileage may vary.