I can't really answer your question directly, but I can tell you what I do to prevent the problem, and / or make it easy to remove when / if it does occur.
Keep the roof clean. I use
Wash & Wax solution on my roof every time I wash the roof (3 times / year). There are times I may use the wash and wax solution but NOT wash the entire RV. I will wax the roof with
Mequiar's wax at least once a year. I have had my coach 20 months and have waxed the roof twice already.
Of course I use the same Wash and Wax solution on the sides after every trip (bugs) or drive in the rain. I also wax the sides of the RV at least once per year with the same Mequiars.
Note: I never try to wax it all at one time, just one side or so when the weather is nice and I just wish to have something to do.
Bugs and black streaks never get a chance to get in my finish, but I do see them, but they easily come off with my next normal wash
Some may question the time I take to wash & wax etc. But I have done the math, I can wash & wax my entire RV in about the same time some can go retrieve a large RV cover and safely get it over the full RV and strapped down so wind can't damage it.
My guess is 3 hrs of my time per month max. But if you do not want to wash & wax it yourself, I strongly suggest paying to have it waxed by a professional once per year.
FWIW, I park my RV under a tree