This is clearly flashback information as we have already seen that Alma finished his record in the eighteenth year of the reign of the judges (Alma 44:24). The offer to reunite the official records in the hands of the political leader rather than the religious leader was offered by Alma, and therefore this incident had to have taken around the end of the eighteenth year of the reign of the judges. Since Mormon has just finished recording the events of the twenty-fourth year, he is not giving us a chronology as much as a background. One of the things that we need to know is why the plates remain with Helaman rather than returning to the political seat where they were kept up to the time Alma the Younger left the position of Chief Judge.