Anyone have any experience with these? My friend has one mounted on his AR10 and he sighted it in Sunday according to the directions. However, when he changed the elevation knob to the #3 spot from the number two spot, he was about 8" high, but when he put it back on #2, he was dead on. Can anyone make sense of this and offer some help?
Edited to add: The original sighting in was done at 25 yards and when he changed the elevation knob, he was shooting at 100 yrds. Thanks.

Tell him to leave it on the #2 spot.