Ascension of Jesus, Asumption of Mary. Why two different names for it?

Mary's umption/dormition/resurrection is distinguised from the Ascension because the ancient stories are unclear about how and what happened. The umption into Heaven, the dormition of the Virgin, and the Resurrection of Mary are all the same set of stories, but told in different parts of the ancient world. Whereas Jesus remained God and Man, Mary remained just a person. I think the difference is to make that clear.