Inconsistent results - Sightmark Laser Bore Sights

I purchased this in 7.62 x 39 to reduce the amount of ammo I would need to use zeroing a new optic on an AK variant. I zeroed my optic with the bore sight in, ejected the bore sight, and then decided to put the bore sight back in to double-check my work. I’m glad I did, since I got a different point of aim on the second try. I tried removing the bore sight and putting it back in a few times, and I got a different point of aim each time. I’m left to wonder if something in my sample isn’t perfectly aligned. I ultimately settled on a point that seemed the most centered result in terms of windage from the various readings I was getting, which was at least good enough to put me on paper with ammo at 50 yards. I’m disappointed I had this inconsistency, since another SightMark bore sight I have in 5.56 x 45 has been completely reliable.