I too have asked this question. Not many people responded, but the ones who did say that it's not as likely to receive codes for peak season as it is for other seasons. We are going around Easter and I am anxiously waiting to see if there are any codes. I made the reservations already and the reservationist told me if codes come out that I can call and get my price reduced.
However, I have also been told that they do discounts based on availabilty of hotels. So not all hotels will be discounted.
I have heard that if there are any discounts that we can expect them around Jan./Feb.
Hope this helps.