That's the whole idea of a narrow-reading spot meter. You're comparing specific points. What you do with that information is another thing. Some people apply it to various Zone models; some do not. The IRE scale has its own set of usage, which might or might not match one's own practical model. For those of us who do both color and black white photography, the placement of the readings themselves necessarily differs case by case. No one shoe size fits all, even when using the very same meter for everything.
But yes, after learning various ZS models, I landed up with a more direct visualize the specific curve in my head approach instead. That takes some experience, film by film; but in the long run it's a lot simpler, intuitively.
Pentax vs Minolta? Having used both, I doubt the Minolta Spotmeter F was actually any more accurate; it just gave more specific readouts. Frankly, both style meters read identically over their full range. As a stated earlier, I found the exterior manual dial of the Pentax quicker and more intuitive to work with.
I never personally saw any sense to those stick-on Zone labels; but it they do help other people, who am I to criticize?
