Let's hope that it wasn't done on purpose - that the rates really did change overnight.
I booked my upcoming cruise with the Early Saver rates just because they were the best for the Grand Suite category (We're splurging on a romantic vacation!) I also like the idea that I can get the OBC if the rates go down any because I know that sometimes prices drop closer to departure.
Anyway, enjoy your trip. At least you are cruising!