Ok I have actually been reading tool tips as I level skills, I get the feeling they were not uniformly written 🙂
I just hit Logic 4 (same old sim) -- And this time it says "can now Read Intermediate Logic Books". It could well be that I missed this on other skills as I hit level 4, painting for example, since I always just do that at the easel, or cooking at the stove, or gardening in the garden etc etc (fishing fishing)... But it still has been inconsistent when I can 'reread' a level 1 skill book under level 4 to continue to skill up. All I can say at this point is that when I introduce another sim I can make them a book worm type and stick them in a chair and let them try to read sub 4 on a level 1 book on all the skills and see if it works. Then 4+ on the next.
I think one of the things that is problematic is that you don't just 'keep reading' while learning, you do have to pick up the book to read it again. Which is fine, I'm not sure how the writer career 'read books' homework tasks works (time reading or number of books read).
The way buffs + debuffs collapse it's not always evident if you are getting bored from something -- and in general I've noticed while working on the writer career, telling the sim to go to the bookcase and just 'read something' they often pick books that WILL bore them, and this seems ... wrong. Why do that to begin with; why pick a skill book below your difficulty level and then read it to bored state.
I still can't figure out how the supposed recipe books are supposed to work, going to keep trying combos out with the new sim in the house.