In many languages the words for year, or month or hour are ambiguous because they all come from the root word circle and they all mean the same thing, namely cycle. So when a culture shifts from a lunar cult to a solar cult the people who use to focus their attention on a lunar cycle, now focus on a solar cycle. But nobody updates the oral history.
930 / 13 = 71 and a half years. Normal lifespan for ancient times.