I gotta say my A/C seems to work very well, especially with covers on the bunk ends. My only complaint is at night we freeze or bake. Is there a thermostat that can be hooke up to the units? We can't seem to find that sweet spot on the unit that keeps things just right all night.
it may need the stock tstat replaced
What brand of AC do you have?
We have the same issue, so we crank the AC wide open and bundle up if need be.
With my Carrier AirV in my Fleetwood Niagara, I set the thermostat at about 3/4 to coldest setting. The compressor kicks off and the unit does not freeze up as it did when on the coldest setting. We utilize the air sweep feature and the bunk ends are pretty comfortable at night. Pop up gizmos make a big difference in the daytime. When it's been in the high 90's and very humid, I will help the AC by spraying the camper with the garden hose (water being cooler than the air) and that instantly drops the temps about 5 degrees and the AC gets the interior much cooler fast.
we have found that if we close curtains on bunkends it keeps the air from blasting you. We use sleeping bags and we are usually comfortable.