I zero the scope at the greatest magnification. I check zero at the lowest magnification. For 99% of my hunting I leave it on the lowest setting (usually 3X) and have made shots well past 100 yards on 2X or 3X and the greater field of view is a plus inside 50 yards, sometimes inside 10 yards. If I need more than 2X or 3X there is generally plenty of time to change it, but rarely much time to go down. If moving from the lowest setting I skip everything else and go straight to the greatest magnification where I know it is zeroed. Even the best scopes will have minor POI changes as the magnification is changed. By only using 2 magnifications I limit the possibility for problems. At closer ranges and on the lower magnifications even if the POI is off slightly compared to 9X it will be close enough not to matter. At longer ranges it might.
