Occam's Razor - in the real world, the payment is tied to progress of the OI. Of course I don't know that for a fact, but it is by far the leading theory in my mind.  The probability that the second tranche has been received as of a couple of days ago - 10%.  

I still give them till tomorrow morning to indicate they received the full amount - $13 million, after that, like I've said, I start to worry, not about receving the money, but about the status of the tech.