I think the "rumor" you are referring to has to do with the fact that a bullet travels in an arch, and your line of sight is straight. If your gun is not held perfectly level, the differences are exaggerated the higher the optic is off the barrel. If you could imagine aiming directly through the barrel it would not matter the orientation of the barrel. Now imagine having your optic a foot off the barrel. Any error in the vertical orientation between the barrel and the optic will cause a large change in the point of impact.
I dont think there will be much if any difference between .83" and 1". You will be better off learning how the gun "feels" when held correctly, it will become mussel memory.