I go through this with our staff all the time - the term "Space Function" used in chapter 10 to calculate occupant load in a space without fixed seating is an entirely separate concept from "Occupancy Classification" per Chapter 3 (and the difference in terminology is very intentional); so a conference room or similar space may be classified as business occupancy, but may apply an assembly function occupant load factor (concentrated, unconcentrated, or standing) per the tabular values in Section 1004. If the predominant occupancy classification on a floor is B, and other conference or similar spaces (e.g., a break room with not more than 49 occupants) on the floor also are classified as B, then the question of accessory use is not applicable for these spaces - it's all B!