I have a Bryant AC unit in my attic. The unit is in the middle of the attic with supply air trunks going to the right and left. The vents attached supply air trunks on the right throw nice cold air. In contrast, the vents attached to supply air trunks on the left throw forceful air but its not cold. I tried to adjust the air flow with levers on each side of the unit where the air ducts meet the unit but of course, it didn't change the temp. Is there any way to have it throw equally cold air to all the vents?