A quick update to the post above about calling at final payment and getting an upgrade. So, obviously this policy can change at any time.
But for me at the two month before the cruise this last February, I called in to book excursions and I asked the PG customer rep if I could get an upgrade quote and she informed me to call in when we reached the 30 day ahead of the cruise.
Now, you should probably ask at final payment, again at the 2 month mark when you can book excursions, and at the 30 day mark. Who knows when they will allow it in the future.
Doug