My model has both PTAC and unit heater in zones. PTAC provides cooling only (heating capacity is hardsized to 0) and unit heater provides heating. And zones have unmet heating hours. All zone equipment operates at sequential order with PTAC first then unit heater. Coil Sizing Details report shows that the unit heater heating coil is sized with 0 outdoor air (ideal load). And PTAC is sized with the correct amount of outdoor air. Is there a way to size the unit heater with zone design outdoor airflow rate?