I have a model in which I calculate discharge rates per hour for physicians. To calculate this I am doing total discharges/model.time(). This takes into account even when they are off schedule. I wanted to know if there is a way to check how much time a staff member spends off schedule or in different down behaviors and divide it by that. I also want to know if there is a better way to do this, for example, filtering out the data when staff is not on shift.