The rules for advancement state that a “class score” is raised by one, but there is no definition for class score in the text. I believe it refers to ability score.

Also it isn’t clear what rations are for in the rules or if they and the cloak each add to item points.

Yeah, I've found it very confusing too.

Does it mean I can improve any score (BSE) or only the score from my Profession (class is a profession, right)? So if I'm a Botany Priest, can I improve only Erudite or also Brute and Skulker? That makes for quite different gameplay!

Minimalist design is one thing, but confusing design is another. How do you guys play? Do you allow increasing one score or any score?