I was looking through my Liber Usualis and noticed that the classifications for Mass (Low, High, etc.) under the general principles and rules do not match with what is published by many diocese, institutes, etc. And then I noticed that some do not even match with one another? So, I went to check with other resources, and only found the following to corroborate the Liber:

https://www.divinumofficium.com/www/horas/Help/Rubrics/Missal1960 rubrics.html

So the question: why and how did the Masses get mislabled or jumbled about? Any ideas?

In my experience, this does not matter for a vast majority of people, but I simply find it so odd.

We see this happen quite a bit, but this seems like a particularly odd case. Help?