Your best hope of getting a discount is to call right away on the day that the discount comes out. There are not a lot of rooms at the Contemporary, and with convention guests taking up some rooms usually there are not many that will be discounted.
We went at the end of Nov/beginning of Dec last year and got a discount of about $50/night, but I called right away. Later in the day I tried to change my dates slightly but I couldn't if I wanted to keep the discount.