When I went through permitting they told me they will go for the highest usage level they can get (probably for the tax man). I replaced a "finished enclosed porch" with a room on the same footprint and will have the same use. They still said it was going to be permitted as "Bas" (regular habitable space). I had to show egress routes just like a bedroom but they did give me a break on <no> AFCIs.
In real life I have to live there so I exceeded 210 on lighting and receptacle outlets but they did give me a handout that said I needed to meet it. My electrical plan was the only thing that went through without a hitch. We went round and round for 6 weeks on structural engineering.
