Don't know if someone said this I didn't read all the post but ,
SSBB has a .78 lead in Japan meaning that SSBB only has to sale 1.5 in NA and in Others to be tired. (Well 1.6 in one of them). So the Japanese difference might be what helps. Think if it does 2mil in NA then all it has to sale is 1mil in Other I think it can do it.