Out for estimate on IAQ, Zoning working correctly at this time, adjusted the static bypass damper, seems to have helped with airflow. The office, is a 10 in duct that then goes to mixing box. With 2 6in ducts and a 4 and the office is a 90 degree bend. Solution remove mixing boxes add wyes for better air flow. Removal of mixing boxes and in installing wyes. Office is much better.