Just in case anyone else is having scaling issues with the new AMD (ATI) 10.8 driver, it's not just you! I'm personally having scaling issues with the new 10.8 drivers on my Toshiba 52XV545U 52" TV.
The setup I have is a 30" LCD connected via DVI and TV connected via HDMI, using a ATI HIS HD 5570. With the 10.7 driver I didn't have an issue with scaling on the TV, but with the 10.8 driver I have to reset the scaling (overscan to 0%) every time I turn the TV back on. I've tried creating profiles and nothing seems to work.