Usually when I see it on others it is in one spot and in the same area. I think that maybe thats where it starts to lose true calibration and where they decided to nudge in a correction? The GXP HUD to analog (mine anyway) is true to about 70, then the HUD gains almost a mile. Say at 74, it will teter and favor 75. Beyond I just watch the HUD and whats coming at me.