I don't follow your logic, and don't know what you mean by 50/50 split. To my knowledge, nobody has ever claimed that any type of historical argument is without hazard, certainly not this one. You're proceeeding as if the question is whether AFS proves anything, and then you point out that most sources say it doesn't prove anything. That's a strawman. Given your dishonesty about the Duncan source (above), and the dictionary of foreign terms, I see no reason to swallow whole your statements about a prevalence of sources.