I got a discount for 3 out of the 4 nites myself just a while ago. I noticed that the last 3 nites of my stay(11/12-11/16) was available for the $55 rate online at disneyworld.com so I called and asked if I could get the discount on my current ressie for the 3 nites that showed online. Yahoo!!! The customer service rep, Vela, was able to apply the discount(which I gave her BAT, but then told her it was the Fall & Holiday resort offer for the last 3 nites. And best of all, she did it without setting up a separate ressie for those 3 nites so I don't have to check-in/check-out/check-in!
I'd recommend checking the disneyworld.com site to see if any of the dates you want are available and then CALL to see if you can apply it to your current ressie. I'm thrilled as I tried 2X this AM and the rep couldn't find a discount for any of my nites.