Instead of adding a new line for the Max Level info, consider adding it in the main line, eg. Title I/III.
This screenshot shows what I mean, it's being added by BetterEnchantedBooks.

Could have it show up only on shift as well.

I think it could help clean up the display a bit, especially on items that have many enchantments.

I prefer not to modify the vanilla tooltip too much, so I added this only when holding shift though. Implemented in 1.3.5 for both 1.16/1.17