I started off shooting split for a couple years. Then I paper tuned my bow and found my arrows always flew nock high, no matter where my nock point was. When I shot the same setup with three under they flew perfect, or when someone else shot the bow split it also tuned perfect. Just something in my technique that caused it. After that I shot three under for several years, till a few weeks ago. I started shooting a longbow last year, and it is noticeably quieter shooting split, so I now shoot split again. I never noticed an accuracy difference from one to the other. It seems like I shoot more accurately now with split again, but I suspect it is because I'm concentrating harder now with the new technique. Three under will get the arrow closer to your eye if you use the same anchor as when you shot split, which may help your accuracy.