I'm not sure about this, but in reading about 3D tournaments in Europe, my impression is that in many tournaments, split finger is required, and 3 under is not allowed. I think there may be some small advantage in shooting 3 under other than just changing the point-on, enough that Rick Welch convinced me to change to it some years ago. While I'm no champion, I find that sometimes I'm on top of my shooting buddies, other times they're on top of me. Most of them shoot split, while I shoot 3 under.