P&S told me to keep my re-coat waxed with Turtle wax to provide the UV protection. Yes it costs a lot for a re-coat at P&S but the factory and others do the same refinishing..same price. AS in Jackson told me they do not p[olish out the stains from oxidized aluminum where the clearcoat is missing. P&S does and they highly recommended them if I needed polishing. Our domes were corroded and clearcoat doesn't cover that up. They buff the metal just enough to remove the corrosion, while keeping the look close to the original factory look. It is different; but our 89 looked so good many SOB owners thought it was a new trailer. Our cost for polishing domes and driver's side roof line down to the windows was $3600 in 2004. We recoated just the top down to the belly line in 2012 for $3000 becaue the clearcoat flaked after an extremely cold winter season storage.
The coating on factory supplied panels that AS buy for their assembly is not the same as the clearcoat used by re-finishers, but it is the sun that does the damage so UV protection is more important than waterproofing. Most members I know use Walbernize RV super seal for their AS. That is what the factory store recommends.
BTW if you have some peeling, cover it immediately with clear enamel spray to stop the corrosion from rain and sun. P&S said just buy a can of clear outdoor spray.