I am wroking on calcuating occupancy of buildings using the zones and the IBC loading factor. The zone stamp is doing all the calculation, and displays it on the plan. This all works great; when the Update Zones command is run, the zones update and the occupany updates as well. Next the Interactive Schedule: I have it set to include Element Type Zone and Zone Category "Occupancy Calculation" which is a category I have created and set to use the occupancy calculation zone stamp. In the schedule fields I am scheduling The Floor(Story) and a parameter custom to the zone stamp, "Maximum Occupancy" The first time the schedule is run It displays everything properly. However, if there are changes made to the zone (either the area changes or the occupancy factor changes) which change the "Maximum Occupany" parameter, the schedule will not pick up this change and retains the initial value. If I try to change the value of the max occupancy in the schedule, the schedule will override my change with the new correct value. This appears to be the only way to get the schedule to rebuild. Does anyone know of another way to make the schedule rebuild? Is there some obscure workevniroment setting? BTW, this is ArchiCAD 13, Hotfix #4.