I'm beginning to think that in many cases the private office active control requirement can be made to work for a VAV system only if each office has a separate motorized damper in the supply duct serving it along with an individual space temperature sensor. Given an example where three offices with similar zoning characteristics are served by a single air terminal, then the occupancy sensor would need to shut off air to the space via the motorized damper so that the other two (occupied) offices could continue to be served while the third office occupant went to a meeting. But if these offices had an exterior wall/glass exposure, east, for example, then control of space temperature would be lost during the period of unoccupancy unless each office also had a space temperature sensor which would act to override the occupancy sensor when the room temperature went out of range. A person going to a 2 hour meeting starting at 8:30 would come back to a very uncomfortable room, negating the ability to comply with ASHRAE 55. The alternative would be for each of these offices to have an air terminal unit. I don't mean to make this complicated but I see no other way of doing this. Am I missing something?