What does a boarding house actually rent, a room or a bed

I'm mostly looking at land and holding patterns, but a listing in a small town described itself as a rooming house with 9 sleeping rooms and 21 residents on the license. That confused me. I thought a boarding house was one person per room paying for a room with shared kitchen and bath.

So the beginner question I can't resolve from reading. Is the model best understood as renting rooms, where you have 9 leases and each resident has a private door, or as renting beds, where a room can hold two or three people and your license counts occupants rather than doors? Both seem to exist. Occupancy limits are set locally and vary a lot by city and state, so the count on that license may mean something different than the count in my own county.

The reason it matters to me is management load. Nine leases and nine private rooms sounds like a normal small multifamily with more doors. Twenty one people sharing 9 rooms sounds like a completely different business, more services, more disputes, faster turnover, more inspection attention.

I'd like to know which version the people here who actually operate consider the real model, or whether that split is exactly the thing a new person shouldn't be trying to choose between yet.