Considering the ridiculous context of the rest of the conversation, (i.e. Dumbledore either pretending to be insane or actually letting some real insanity slip through) is it too far outside the realm of possibility for that comment to be a joke? It seemed like Dumbledore was going out of his way to screw with Harry in this chapter. Even if the machine actually does what he said it does, I could easily see the comment about "how much work it took to nail that down" being a joke Dumbledore told for his own amusement, knowing that Harry was too young to "get it".