It is a huge savings! We are paying close to what we paid for virtually the same sailing/ship in 2011, with a slightly better room category this time. I hope for the sake of the employee who came up with it, it results in significant new bookings for Disney and not just repricing. They must have seen something really troubling in their projected bookings. Either that, or decided it was time to create more buzz around the cruise line now that the Wish's publicity is slowing and they are trying to get things back to normal. I hope it works.
Update: After 5.5 hours of Disney hold music, I was finally successful. I talked to a fantastic agent who was able to make the switch to the existing reservations, and the savings was indeed $2,600! I am so glad you told me to book the dummy cruise, because I would have had to deal with canceling a real booking now and waiting to get my deposit back. That worked out really well and took the stress out of waiting the last hour or so. Thanks!