Update. I just got off T*****t support chat and they said they don't think the number changed. They think an update is being performed and the 10 keys should return in a day or so. So maybe the change to 2 isn't permanent.
More information about the keys though. This is cut and pasted from my chat with TN Support.
L***s L*: I see, thanks for your clarification, it is the same problem at my side, it might be caused by an unplanned maintenance in the T*******t site since we never received any notice from the upstream team either, sorry for the inconvenience that have been brought to you. I suggest you check it later or tomorrow, if the problem still remains, please feel free to let us know, we'll escalate for you. By the way, most T*****t key can allow multiple activations, an 'Retail' key can activate 10 different machines.
Just thought I'd pass that bit of info downstream here for those running short on keys