Ultra breeze vent cover mounting hardware

I purchased a "ultra breeze vent cover" for my Roadtrek in 2012. Didn't think about it after installation until I was washing the roof of my motorhome and noticed running rust from the mounting hardware. Wow, imagine my surprise when I removed the cover and found the mounting hardware was totally rusted, there are big rust spots where it was mounted to my motorhome, the screws provided are longer so the four holes where the hardware was mounted are stripped out. There is a YouTube video where the fellow is able to install the unit in 3 minutes or so. I wonder how long it will take him to rub out the rust spots after a few years. The mounting brackets hold the water and moisture next to the surface of the roof, thereby causing the oxidation. Unfortunately, it does have a tendency to rain where we live, Washington state, west side.