“In other words, to Rav Moshe, doing a chessed for this woman trumped his time.”
At the very same time, to a caller who should have known better, Rav Moshe politely told him (the story goes) that the early AM hours are for his learning, not shaylos. The story with the woman is an indication of his greatness, not that people should ask him the silliest questions at all hours of the day.