I quickly read this thread and if a couple items were addressed, I missed them:
1. How OLD is this system and have the COILS, particularly the Evaporator Coil, at the front of the unit, under a sheet metal shroud, been Cleaned?
2. It's ducted, so is the ducting OK? I don't have a ducted, but I understand there can be problems right at the unit where flow is reduced.
3. On the roof, is there baffling (foam blocks) along the vertical edges of the Condenser Coil, so air being exhausted out the sides, isn't being sucked around the corners of the Condenser?
Remember, a 20* "Split" doesn't mean the coach won't get below 80* if it's 100* outside. Once it cools the interior to 95* then split means the cool air can now be 75*. If it cools the interior to 80* then you could (at least theoretically) drive it down into the 60's. But, as mentioned, if the A/C lacks the capacity to bring interior temperature down at all, then this can't happen.
