Not getting full 1yr protection on 2nd machine

Hello, I purchased NIS for Netbook 2010 in sept 2010.

I installed it on first machine in Sept 2010.

I just installed it on second machine today 8/18/11. The NIS on second machines shows that I have 16 days remaining, instead of full year of protection.

 

How can I make the coverage for second machine for full year from the day I install it??

Thanks