Hard for me to believe that that many people shoot 3 under. I've tried it a couple of times, and just didn't like the feeling that I had lost some control. It's also hard for me to believe that just raising the nocking point makes it OK. If the bow's not tillered for it, it has to throw things out of balance.
If you do raise your nocking point, I would think that it would be wise to raise the shelf a bit to compensate, so that your arrow doesn't "run downhill" to the shelf and introduce another force vector to the arrow. The closer you can get to horizontal and clear the shelf, the better for performance. This is just theory for me, but it's based on a lot of trial-and-error archery.
I do know it's a fact that a too-high nocking point robs energy from the arrow. I avoid anything that does that. I want every pound I pull to go into the arrow.
After shooting for nearly 50 years, I've found that if I try to change my style, I tend to revert under stress (DEER IN FRONT!!). It's best for me to stick with my long-term habits. Make that, GOOD habits.