[ingalmi]

I’m assuming window shades are down and limited to no shade. You’re doing pretty well with only one unit running. When outside temps get above 85 the unit is pretty max’d out. Shade is your friend when trying to cool a metal box. Ducts both supply and return are a well documented problem and a good place to start looking for loss. I know this doesn’t answer your question but some of us have spent many hrs improving supply ducts, opening return ducts, and trying to find a balance. Difficult to do when you only have one unit working. Good luck