Scalarworks has produced a video that shows very graphically how well their mounts repeat zero after being removed and replaced on the rail. The test shows 100 shots being fired in groups of 10 with the optic being removed and reinstalled between each volley. The optic steadfastly returns to zero in each case. They didn’t just test the LDM on any old carbine. They mounted it on a .308 battle rifle known for being very hard on optics, the FN SCAR 17.
In my own testing, I saw no discernible zero shift when removing and replacing the mount.