Time for renewal, but I can get it cheaper by buying 2013?

So I got a message that I need to renew my subscription in 30 days (NIS 2012). The charge for the renewal is $70USD.

I did a quick search on Amazon, and found 2013 NIS for $25, which I assume comes with a one year subscription.

 

If this is the case, then the obvious choice is to purchase 2013 via Amazon and save $45USD.

 

My concern is that when I load 2013, Norton might consider the product as part of my existing subscription/account and the renewal clock won't re-set.

 

So, my question is, if I buy the 2013 product and install it "over" the existing 2012, will my subscription reset to a year, or will it "piggyback"on the 2012 product, and I will still only have 30 days ledt?

 

Thanks!