I found a website that has a lot of opinions about skate sharpening and related equipment.
Figure Skate sharpening myths (https://rocket-skate.blogspot.com/search?q=myths)
It claims that chrome relief zones are created by hand using a belt sander, in a very crude inconsistent way, so there is no point to trying to keep the chrome relief zone (on blades that have them) of uniform height.
I think that would also mean that the working part of the blade might not be centered with respect to the sides of the blade, or might be centered in a non-uniform way.
Is that currently true for the major brands (e.g., MK, JW) for those blades that have chrome plating?
BTW some of the opinions on that site might be slightly self-serving. E.g., it implies that many sharpening machines that people on this forum like, can't do a good job. And some of the blade info is out of date. (It was written in 2012.)