Why are you using inches or cm at all? You have a reticle, use the tape measure that is 2”3.5” in front of your eye.
I agree with this and using the reticle as a reference dimension.
I'm trying to understand the theory of the system as it is applied. Its essentially metric (https://en.wikipedia.org/wiki/SI_derived_unit), but it appears common to mix in yards and inches when describing distance, height, or any other dimension when not looking through a scope at a target. From a science/math viewpoint, its sloppy and not intuitive to mix units. Not saying its better or worse, just want to understand what the state of practice is.