Disc Title Number vs. Disc Number?

[Alsweider]

When I use the auto-tagger to tag from file name, I have the options to use "disc title number", "disc number" and "title number". Correct me if I'm wrong, I suppose this means for example:

Title number: The album has 30 tracks, so 30 possible numbers.
Disc Number: When an album has 3 discs, you use 1, 2 or 3.
Disc Title Number: If every disc of the 30 track album has 10 tracks, you would have 1-10 numbers per disc.