nothing different than what you mentioned. both are made on the same assembly line.
Rockwoods tend to be cheaper because there are way more Rockwood dealers than Flagstaff dealers.
RVW and RVDirect are the two biggest online RV dealers and they both sell Rockwoods, not Flagstaffs.
so, since they have some of the best prices in the country, other Rockwood dealers have to compete.
there was only one online "wholesaler" Flagstaff dealer and i don't think they are in business anymore.
not sure why FR pushes the Rockwood line more than the Flagstaff line.