You shouldn't be seeing a difference in magnification with coatings, assuming you're referring to anti-reflection coatings. You shouldn't experience more than a fraction of a wavelength of difference, which isn't enough for the brain to be concerned with. I suspect childhood trauma. ;-) You'll get used to a difference in close-focus between eyes, probably around age 45-50. My eyes differ by about 14", but the brain can cope with that, given time. At least, mine did. My daugher laughs at me as I move books closer, then further away, as I search for a good middle-ground, even with non-prescription readers on. I have mild astigmatism in both eyes, but even in my dominant right-eye, which I do most of my observing with, it's not enough to cause poor imagery at the eyepiece. I remove my glasses at the eyepiece and use the focuser to accommodate. As long as my astigmatism doesn't get much worse, I see tack-sharp images. Knock-on-wood. When I can't detect Saturn's polar hood in my "planet killer", I'll know it's time for lasik. Crap.