I have one bedroom(son's) that is always the hottest in summer and coldest in winter. Very noticeable when you enter it. This room is the first or second duct off the main trunk. I have checked the obvious, leaks etc. also sealed the boot at the register. Is there anything I'm missing? Is the suppy air rushing right past this duct? Would a larger supply duct help? One other thing the return is in the hallway right outside the bedroom door. You can feel the airflow pretty good.