IMO bow grip is more responsible for left - right misses.

If you are new to a round sight - How do you aim at diff. yardages. Are you centering the pin or the sight?. At longer yardages - you will really see a vertical diff. if you are not consistant in the way you sight the pin.

Poor nock location and fletching contact are another big cause of vertical misses.

You have to pull pretty good into that dually to keep the wall. If you are inconsistant in how much you push/pull - this can also lead to high or low misses.

good luck