I don't know about the VX-3i, but I have a VX-3 (3.5-10x50) with the cds. I didn't really want the cds, but it was all they had in stock to exchange for the one I returned without cds...lens was a dud from factory. Anyway, I ordered a dial for the ammo I shoot, and although I haven't actually tried it at any distance, I can say it returns to its zero perfectly. I have cranked it all the way out to 500 yards and back to 100 a bunch of times at the range, and it always stays dead on.