???
MrStevee,
You got me confused now, how can pumping a system down and just vaccing out the suction side and parts of the liquid line get rid of moisture? Surely most of the moisture will be in the highly hygroscopic oil that goes with R404a and most of that oil will (hopefully) be in the compressor...

My personal diagnose from a couple of thousand miles away?
Flows...
You are either looking at a problem with the airflow or with the refrigerant flow, it could be as simple as dust in the airside of the coil or oil in the refrigerant side.

Just my 4p