Interesting. Most of the sources I've found are citing the episode Test Pilot from season 1, in which George is told he could live to 150, and he then says he has "a good 110 years ahead of [me]!" I wonder where this discrepancy comes from. Perhaps it was retconned when they realized that the ages they gave the characters (George 40, Jane 33, Judy 16) meant that Judy was likely conceived when Jane was 17 and George was 24.

Here is one of the sources I've found. There are many others, but all seem to be referencing the same episode.