Heck, he could have labeled them like they do Stars... O, B, A, F, G, K, M... and we'd have to make it work... Even the old Weston Master meters are labeled with incomprehensible sequence U, A, (arrow) C, O.
I know you are trying to clarify but I think the main point that needs to be clarified here is the two places where Zone is considered:
...What you see and meter at the Original Scene
0 Pure black, open doorways
I Near black, dark objects in deep shadows
II Darkest part of the image in which slight detail is recorded
III Average dark materials and low values
IV Average dark foliage, dark stone, or landscape shadows
V clear north sky; dark skin, average weathered wood
VI Average Caucasian skin; light stone; shadows on snow in sunlit landscapes
VII Very light skin; shadows in snow with acute side lighting
VIII textured snow
IX glaring snow
X light sources and specular reflections
...Where you place them or they fall on the Finished Print
0 Pure black
I Near black, with slight tonality but no texture
II Textured black
V Middle gray
VIII Lightest tone with texture
IX Slight tone without texture
X Pure white
The same Roman Numeral series is used in these two different contexts. Usually the context is clear.
But when you look at a grayscale printout, it is very easy to get the contexts mixed up.
It kind of short-circuits your brain if you aren't careful to keep the scene and print contexts separate.
Here is kind of what happens when you take a print and use it as a subject:
The print, in even lighting, only reflects about seven zones (I just metered my grayscale chips from the "Grayscale and Cat" and they barely covered seven Zones on the meter)
Meter reading Zone I = Zone 0 chip
Meter reading Zone II = Zone I chip
Meter reading Zone V = Middle gray chip
Meter reading Zone VIII = Zone IX chip
Meter reading Zone IX = Zone X chip