This will be probably downvoated. Probably it is not an anwer to your question, and more likely a relief to myself.
The basic idea behind Pantone guides is a good one. Color theory has being evolving and chemistry manufacturing pigments too.
Pantone started in the '50 with the abilable chemistry to produce pigments, and they started the system based on thoose imperfect pigments.
They started with just some swatches with just 3 digits because they did not glimpse that in the future they would need more.
As the chemistry of the pigments evolves let us say to provide a better performance dye, a less toxic ingredient, more durability, the standards for printing need to adapt a bit.
Some years ago they had a downloadable pantone catalog for you to print with some aproximated values for CMYK swop2 standard conversion. Years later they changed the values again.
But there is a chance they could do a better job making this conversions. In my opinion Pantone sometimes makes some dumb decisions.
For example, they provide the conversion matrixes to software like Adobe and Corel. Why in Earth the exported value does not match the screen output (and I do not mean the monitor output to the viewer) with the rendered value on the file. No idea. There is a chance the fault is from Adobe or Corel software. But in the case of the printed swateches, cant they add 1% to cyan to darken a bit more the red to make it visually better?
The new colors that they release, a new green, has now a number that has nothing to do with the previous simmilar greens. The libraries jump from one number to other with no reason.
So my answer is. No idea. Live with it.
Thanks for reading... try not to be too harsh downvoting this guys n_n.