No. IIRC, the only reason propecia has that disclaimer (as does rogaine) is because they would have needed to spend more money on further trials to specifically state that propecia would work on frontal thinning. In other words, it’s basically just out of legal necessity. Of course propecia “works” on frontal thinning too - it’s not like a different mechanism is involved in balding four inches down your scalp. I myself had ridiculous “results” on propecia the first time I took it and I basically only had frontal thinning… lucky me. Someone better-informed on this can correct me if I’m wrong, but I think it’s roughly along those lines. I think you need to stop overanalyzing things for your own good, and I mean that in the nicest way possible.