In this context, the ages seem designed precisely to flag the nonhistorical sections as nonhistorical. It’s as if the text is shouting, Just to make it clear that the flood isn’t the same kind of account as the destruction of Jerusalem in the year 587 B.C., we’ll give the characters in the first one ages of many hundreds of years, while the people in the second one will live normal life spans. That’s a sign no one can miss.
