I don’t know if I’d apply a second wet coat ....you might chance forming wrinkles in both layers of existing clear coats,.....Mike, how many coats of Dullcoat have you applied?....were there any possible impurities on the roof before the Dullcoat went on?.......when this happens, the easiest remedy is to LIGHTLY scuff the smooth areas with fine scotchbrite ( grey or red) wipe the roof down with a clean microfiber and visual inspect for flaws or fuzzies left behind,.....once you’re satisfied the roof is slick & smooth, apply one even MEDIUM coat in one motion and observe the finish,....a hairdryer speeds up the curing process,.....inspect your work and either repeat the scuffing process or apply one more medium coat in one fluid motion to lock it in,......also, test your can on a piece of scrap to be sure it’s not spattering,.......I’ve long since stopped using Testors Dullcoat in favor of Krylon’s flat clear....that product comes out at a higher pressure than Dullcoat, and the can lasts ten times longer for less money,....
Pat
