I have to go with
Cliff’s logic on this one. The manufacturer might specify the range when they make their prototype but over the course of the production run the pots themselves might drift as they get different batches, causing the pots and knobs to be in different positions from unit to unit to get the same sound, even though they’re supposed to be identical. We correct that drift by turning the knobs until the units sound the same (and then pop off the knobs and reattach them if we’re so inclined to fix the cosmetic problem) but the fix was turning the knobs so the sound matched.
I don’t care whether the knob positions on the modeler match the reference amp or my amp either. Because of the production drift I know it’s unlikely they’d all be the same, but they’d be close enough and with a bit of fiddling I get what I like. Besides, if I was to want to die on this particular hill, then my banner would be make everything match, positions and ranges, colors and shapes of the panel and knobs and switches, entirely skeuomorphic. But it wouldn’t make the unit sound or behave any better and would burn a lot of development dollars which I’d rather see spent on other things.