Oh ok cool man. I hadn't even heard of that...which isn't surprising since this is my first AR build and I haven't had much time to research optics. But here's a pic of my rifle as I have gotten it so far:Most people (myself included) have the red dot sight, and then a magnifier in front. when you don't need the additional magnification, you can either remove the magnifier, or get a flip to side mount. AimPoint has a nice system, and you can find some other magnifiers ( i put a 5x on one and a 7x on another) just look around to see what suits you best
So how do the magnifiers work? Are brand interchangeable? I didn't see any on Aimpoint's website.Yes taking it off and putting it back on can make it off a little bit...shooting at coyotes though at 100 yards it won't make a difference.
Check out Magpul Dynamics: Art of the Precision Rifle.
They swap scopes between rifles at one point and it keeps the zero pretty good even between completely different systems. So yes it can, will it make a difference? Probably not unless you're competition shooting.