Elder Erwin Lamoreaux (Grandpa) started his mission in September 2011. As you can see here it says the length of service is 24 months. That would mean that his mission would have been over in September of 2013. That was not long enough. So he went online to his mission webpage or whatever it is and extended his mission for another 24 months. That means he will be serving until September 2015 - one more year, that is if he doesn't extend again.