IF it were up to Albandit you will probably have this post moved to the paint, and body folks as he is a stickler for having round pegs fitting only into round holes, lol, blah, blah, even though your paint issue is actually OEM.
"old Man" is spot on. The only thing I would add is that all chemical paints are not waterproof, meaning a good hard wax job will greatly fill in those little micro-holes in any paint, especially paint under constant UV destruction. I said hard wax, as opposed to those fancy liquid polymer types on the many shelves. Much more work, but lasts a lot longer. Use the fancy stuff on those areas which you can reach 'mo easily, i.e., after a wash job. Once a year for the roof with the hard stuff. Just my 2 cents, lol.
Here in Alaska, I fixed the same issue to my roof top by sanding, priming, and painting flat black as that shade absorbs sunlight which helps to heat up the interior on very cold days, and if it gets really hot in the summer, say 70 degrees, I just roll down the windows. (I have tossed out any A/C units in favor of down rolling windows, and opening up vents, blah, blah.). Flat black on my hood too.., as it reduces sunlight glare when the sun angle is such, and so. Our various police forces do the same in order to gain better visuals of the road, and hazards ahead under such conditions, etc.