I've heard of people using a 1" nock point when shooting 3 under, but this is the first time I've heard of someone using a 1" nock point for split fingers. Could you describe your bow for us?
I found when shooting 3 under that I could get a lower nock point by reducing the pressure on my ring finger and increasing the pressure on the other two. I also found that the consistency of arrow flight was much improved by using two nock points rather than one. I don't know whether either of these things are applicable to split finger.
Sometimes split finger shooters press down on the nock with their index fingers, which causes a bend in the arrow, and this can cause squirrelly things to happen. This can usually be avoided by making sure your string elbow is as high or even a little higher than the arrow, and making sure you're pulling with your back muscles. Generally, pulling with your back muscles solves a lot of problems, so if you're not sure about this, check Arne's (Moebow's) videos on the subject.
Other than that, it could be a tillering issue with your bow, which is why I'm wondering what you're shooting.
I know I'm wandering, but nobody else has chimed in so far, so I thought I'd throw in my 2 cents.