Anielka, who has the world's greatest database on JA and her relations, and who used to share everything she ever learned about her with us at Pemberley, once worked out that the dates in Persuasion, are, indeed significant dates for JA's family. And yes, she and I think it was a family joke, because most of the 'birthdays' seem to be Austen family deathdays.Somehow , the idea that they are simply 'fillers' which JA was alter when she polished the novel, doesn't wash with me.