Your study aligns with this this one:
https://heatisland.lbl.gov/sites/heatisland.lbl.gov/files/Cool_cars_final_LBNL_project_report_v015_2011-08-08.pdfI cannot find the article, but I read that these darker colored MH's could easily downsize their air conditioning units if they were a lighter color. Considering that the large Class A's are typically owned by retires full timing in the warm sunny climates of the southern belt, I would have to agree.
I know we camp year round and could probably benefit from a black roof due to our ocean moderated climate but would pay for it when making trips to areas that actually have sunshine. I have owned one black vehicle without air conditioning and can attest the sun can make things uncomfortable when I lived over 10+ degrees farther south.