The way the code reads is if a building is within 1500 feet of the next one, they must have impact protection at least 30' above the roof of an adjacent building.
Where you start to get into a grey area is if a building was put up and there were no adjacent buildings at the time then those 30' and 60' numbers are from the ground. But if another building is put up inside that 1500' range at a later date, it technically no longer meets code.
I would have to think that the building department must know this will happen and they might assume there will be a taller building next to it in the future. Of course that implies forward thinking and logic which rarely apply to the building department.