Thats it.
Anna Obama and Stanley Ann Dunham are two different people.
Perhaps you are unaware of this, but Susan Blake (of Seattle) claims in an interview that Stanley Ann Dunham showed up at her house on or about August 25th, 1961 unfamiliar with diaper changing. Susan Blake specifically remembers the date because she was vacationing in Santa Monica but had to leave because of the fires there.
Susan Blake obviously knows and recognizes Stanley Ann Dunham because they went to school together. She is also quite certain as to the date. The difference between August 25 and August 19 is 6 days. Not a terribly significant difference in my opinion.
Blake changed her story after coaching and one 0bama supporting witness with a memory she claims to have is not enough to prove anything.