You have talked to the right people, I would go back to them, ask again. they should be able to help. If not it's because they are not willing or maybe they really don't know, but that seems unlikley. make sure you get their names just in case you would have a problem in the future, I have been in situations where one agency tells me the oppisite of the other, I try to stay out of the middle. I just clean to NFPA 96 standards, document everything, any dificiencies in the systems to include inaccessible area's of the duct work short electical wires to the fan and so forth.