PH; I think you need to go to the range set up you pattern sheet @ 16 yards, make sure you take a rifle bench shooting position to ensure same mount each time you shoot your pattern, this is an old English methold proven many times.
Correction of POI is 1/8" for every 2" off of center,ie: if pattern high you need to drop comb higth 1/8" for every 2" of movement@ 16 yards. Make sure you have your gun mounted the same every time, also check out Lyman fiber optic sight made to correct eye cross-dominance. You should be able to correct this problem yourself,
enjoy your gun. Acorn