At a recent ship inspection the carnival rep was asked this question, and the answer is that most of the time the guests that pay the highest rate for a certain category guarantee are the first that the cruise lines appoints the upgrades to. My clients have been asking me this question and I am glad to finally know the answer.
We sailed on the Carnival Triumph in May 2005, I booked my room only 65 days befoer the cruise, this was our first cruise ever. While talking to my dinner mates I discovered that we booked the soonest and payed the least and we were up graded the most out of anyone. We booked a guaranteed 4a and were ugraded all the way up to the Lido deck. Everyone at our table paid more for the same thing and got less. There really is no rhyme or reason for the upgrades........RICH
If you want to get an upgrade, your best chance will come if you book a "guarantee" stateroom. These are among the least expensive staterooms, but you also don't get to choose your stateroom. However, there really aren't any bad staterooms on a cruise. In this category, you are "guaranteed" at least the category that you booked, and upgrades are usually from inside to best available inside, oceanview to best available oceanview, balcony to best available balcony, etc.
It doesn't really have anything to do with decks, it is according to stateroom category. The guarantee reservations fill in the empty staterooms after the full-fare guests in the stateroom category have paid in full. The cruise lines know the anticipated passenger load for the sailing date and set aside a few guarantee staterooms on most sailings. Try to take a cruise in the off-season, i.e. after Christmas and before spring break, or the fall months after Labor Day to mid-December (not Thanksgiving).
Have a great day!
**edited to remove commercial reference***
Barry, that is just one theroy as put forth by some TA's that hope you pay more and book sooner. <> Really, exactly how they determine upgrades just defy's explaination. Just when I think I have it figured out they go and do something totally differant. I doubt if they can even explain it to anyone.