Yeah I tried getting the sidegrade today too and the coupon didn't work. I wrote CP a note and got this response.

Response (***) 11/24/2011 03:47 PM Thank you for contacting Support. As stated in the Coupon information, the discount does not apply to special pricing, upgrades, etc...

You can use it on the Full Price option for Poser Pro 2012.

******* | Customer/Tech Support
Smith Micro Software, Inc. | www.smithmicro.com ** Customer (******) 11/24/2011 02:45 PM Customer Email = ********
Customer Name = Mark
Product or Seller Info = Poser 2012
Order Num =
Problem = Is a "sidegrade" an upgrade? I can not get your 60% off black Friday coupon to work on an order of a sidegrade from Poser 8 to Poser 2012. Thanks

 

One thing I noted, if the coupon can be applied to the full price, it lowers the cost to about $200 (40% of ~$499.99), so you still save some money as the sidegrade price is about $250.