Condo inspection commercial or residential?

Six units under on roof and short term rentals allowed.
What differentiates between being commercial or residential?
InterNACHI contract language for residential agreement states four units as maximum for agreement to cover inspection.

Thanks in advance.

I would go with what your E&O insurance company says it is

Pretty simple:

Are you inspecting ONE unit? Then it’s a condo.

Inspecting the entire building? then it’s commercial.

InterNACHI contract language for residential agreement states four units as maximum

That’s not just InterNACHI. That is (almost) universal in the Real Estate industry to differentiate between residential and commercial.

Most loans, insurance, etc, use the same distinction.