The meat of the article is:

>the fact that there are 234,000 unrecorded deaths in the Japanese population means the often-touted life-expectancy figure of 82 years for Japan now has to be considered suspect

Not sure how you can argue against that reasoning unless you can show Japan's life expectancy calculations have nothing to do with official estimates of how many people are currently older than 100 (which is possible).

Your example doesn't follow the spirit of their argument at all. They aren't proposing their own average, and their evidence involves far more than one data point.