Just got off the phone with Norton support. They told me that starting with NIS 2008, one can't upgrade from NIS 2007 to NIS 2008 for free. He said I would have to either continue to use NIS 2007 until the subscription runs out or lose the money on NIS 2007 and upgrade to NIS 2008 for the going rate.
I found this out through chat. I'm going to try calling them to confirm this.
