Just a guess but if you slow the fan down (hope fully you have adjustable sheaves to get your attained 90 degree split) will your building temp come up to temp. If not take something and block the air flow into the unit to get the 90 degree delta on all three and see if the building temp comes up then you know your moving way too much air. And if you try this and the air temp comes up then you will know what the problem is and you can figure if the calucations are incorrect. I am old school and I always try to prove why!