Are you venting the A/C thru the duct vents or all air from the ceiling vent under the A/C?
Venting thru the ducts is quieter.
Place a separate wall thermometer beside the thermostat to verify any temperature variation between the two ... actual temp on wall thermometer compared to temp shown on the thermostat.
2012 Fun Finder XT 276 Toy Hauler & Harley Davidson Ultra Classic with Condor wheel chock
2014 Dodge Ram 2500 AT 4X4 Crew Cab 6.4 L Hemi, 373 gears, tow package, Rambox option, Revolver X2 tonneau cover, Equal-I-zer anti-sway hitch.