OK, appears that Occupancy B building does not require smoke detection other than the control panels (as mentioned). The other smoke detection installed in 95% of the building is considered "non required coverage". NFPA 72 is confusing regarding this, as in the first article it says, if it is non required or not, you must comply with this code. Which implies that you have to install throughout anyway.
Then the second paragraph says, install them where you want, and coverage of the rest of the space or building is not required.
It's almost like these two paragraphs conflict, or should have been in the same paragraph to have one qualify the other.
