About expiring and renewing

I have installed Norton Security for 5 devices with expiring date 12/12 2015. Then I wanted to renew, but on my account Symantec wanted me to renew with 10 devices, instead of 5. No thank you.... so I bought Norton Security, but for 1 device yesterday, with expiring date 9/27 2016. I hoped then the expiring date for the new Norton would be 12/12 2016? If it's not going to, I'll never buy Norton again.