While it's true that the postman always rings twice and that would be a nice wink to the movie, once again he said **something** no one will expect and not someone. It's an old quote, maybe he already changed the story, maybe it will really be the postman, we don't know. But that's not what he said in that quote:
It's just to avoid that this "fake news" spread once again
And just to come back to those "lucid approaches", the unexpected thing seems really something that will challenge the usual rationality with which Sophia kind of "defuse" the situations that happened so far.
Unless it hints at Sophia being in an altered state, e.g. drunk, but, personally, I really hope it's not the case, it would feel like a cheap shortcut IMO.