Buying more than one Norton IS = extra subscription time?

Hi, I've been wondering about this for a long time, if I buy more than one subscription of the same year, would I be able to use it as extra subscription time- ie, if I buy 3 copies of Norton IS 2013, would I be able to active each copy after the previous one ended?

 

I occasionally find huge discounts on Norton IS, like the most recent one: 15 mo subscription Norton IS 2013 for $24.99 

I'm wondering if I buy 3 of them for $24.99 each would I be able to use them one after the other? 

My current subscription (NIS 2012) ends June 2013, so I'd activate the first copy which is 15 months so that's Jun 2013-Sept 2014, then the 2nd copy which is Sept 2014-Dec 2015, and copy #3 which would send me into 2017...

woudl that work? 

 

thanks in advance, i've been pondering about this forever. it's a chance to save a hundred bucks.