This winter I've been experimenting with 3-under after 40+ years of shooting split, and so far am really liking it. Recently I've come across several posts recommending two knock points on the string, one above and one below the arrow. The reason given being, to keep the arrow from sliding down the string on release (presuming a knock-point above the arrow). Now, I've always knocked the arrow below the knock point and, to my knowledge, never had an arrow slide down the string. The only difference I can see beween split and 3-under is which finger is immediately below the arrow - the middle or the index. Never heard this recommendation for split shooters. Am I missing something?