It doesn't work like that. It doesn't extend your warranty 2 years. It extends your warrant TO 2 years after phone purchase date. If you bought your phone with AC+ in January 2017, your warranty would end in January 2019. If you bought your phone without AC+ in January 2017 and added AC+ in December 2017, your warranty would still end in January 2019.It would have been nice to have the extra months added to my AC+ now. I know that that won't happen, though. That would have put me into 2019 for coverage, instead of the end of 2018.