As far as I can recall, this is new this year. They adjusted the seasons and rates right before releasing the spring discount early this year, thereby minimizing the discount a bit - kind of smoke and mirrors if you ask me. Raise the rate, then offer a percentage off. Someone with more experience may remember them doing this previously, I just don't recall.
I do recall last year, they raised the ticket prices before releasing the fall discount which, again minimized the discount for people booking packages after the ticket increase. I helped a family of 6 with a trip last year. They booked a trip at rack rate for November 2012 about 9 months prior to check-in. In the summer 2012, ticket prices went up, discount was released and we checked to see if they could save money by applying the discount - nope, in fact with the "discount" it was now more than what they locked in at rack because the ticket prices were now higher.
With ticket price increases imminent, I would suggest anyone looking to book a fall package with tickets, book now as the next discount may really not be a discount at all if you book after the ticket prices go up.