I never used the product that your asking about, so no help there. It sounds like Jobshop 600 made by SC Johnson, it'll etch aluminum and is a heavy duty degreaser. I use it but not on finished surfaces.
My experience has been that if the roof is treated like the sides(kept clean) the streaks don't appear.
Most times I believe the streaks are diesel exhaust from out on the highway or if your trailer sit's around diesel trucks like mine do. There's always a ton of diesel exhaust on the roof of my trailers and toterhome after a long trip. I wash the top first and then the sides the streaks don't appear.
I've had 4 enclosed trailers and a aluminun roof toterhome. I've washed them hundereds of times and don't have streaks.

One time I bought a used white 40 gooseneck trailer. I used a 7" wool buffing pad with car wax and removed black streaks and had a killer finish when I was done. Used liquid wax so I could squirt it on my buffing pad and the trailer. Car wax is the best way and protects the finish at the same time.
I used the 7" buffer on that 40 footer and used it for 2 years and sold it for more than I paid for it. I also replaced every exterior screw in it also, so it was nice. Shiney sells fast when it comes to trailers from my experience.