the chat options are different when you run out of noted clay
so basically when you can unnote the options are repeating previous task (unnoting) and "other" and when you dont have noted clay anymore the options are different.
Also sometimes it seems like it sends the butler back with some clay since after ~5k tabs i usually have like 20-30 clay in back
edit:
also the paint cuts of the profits after 1M and doesnt show exactly how much money you made