A couple of things I have discovered over the years, firstly most manufacturers seem to skimp on the clear coat on that top rolled ridge cap. I don't know if they figure that because it is up top you won't see it and done intentionally OR the guys spraying the clear coat onto the top ridge cap aren't overhanding the gun properly and keeping the gun perpendicular with the surface. I noticed how thin the clear was on several that I have painted when prepping the top rolled ridge cap, the sides took a bit to sand but barely breathing across the top cap with a DA and it was through the clear to the base color in an instant. I watched a guy at a local paint shop spraying the top area of a Dutch Star while I was dropping off a friend to pick his Diplomat up from being fixed from an insurance claim and I could visually see the clear coming out of his gun and the majority of the clear was making it to the side of the coach but very little over the rolled top ridge. I mentioned something to the shop manager that he may want to instruct the guy on the scaffolding to use and overgrip on the gun and keep the gun perpendicular to the roof top and it will apply a more even coat of clear and he just looked at me with content and disgust so I shut my mouth and left. I felt sorry for the owner of the coach because he definitely was NOT getting what he was paying for and will be right back in the same predicament in a few short years. This was also the most expensive shop I got a quote from when I was looking for quotes for our Dynasty. After seeing that, there is no way I would trust them with my coach. Like others have already mentioned, the dark colors and rooftops, windshield eyebrows, etc are all exposed to UV and more subject to having issues but I have painted vehicles that see UV on a daily basis and the hoods, roof and fender tops have looked good for 12+ years easily. My 1986 Suburban was my daily driver and I stripped it down and repainted it when I first purchased it and drove it daily for 16 years and it looked as good the day I sold it as the day I rolled it out of the paint booth.
The second thing I noticed on DIY projects, is the use of clear coat from an aerosol can to repair peeling clear don't seem to hold out as long. It will look good for a while (longer if stored indoors) but without catalysts, isocyanates in particular, in the clear coat the durability and UV protection just isn't there.
Mike