For reference, here is the transcript. Almost certainly she was in night school in the Fall quarter and was not taking her courses by correspondence. You can see in the bottom right corner of the transcript her credits for extension courses. If you read the fine print you can see that the university distinguished extension courses from correspondence courses by an "x" in front of the course number. Her neighbor Mary T. in her interview said she was babysitting for Ann while Ann was taking night classes at the university, and as I recall that recollection related to the period around Feb-Mar 1962. Looking at the credits and courseload, it appears she was taking the same type and load of courses in both the Fall and Winter quarters. You may well be right about the date being Sept 19 and not Aug 19. The date on the transcript could read either way, and we have your recollection to rely on.
Correspondence courses were extension courses. I know. My little sister did exactly that which is exactly how they appear on her transcript also.
Unfortunately, the thing I haven't yet said is that it may be that the night school courses were also extension courses. And I have a vague recollection that may have been in fact the case from something another friend did in exactly that time period.
Of course the only evidence we have that the winter quarter classes were night school is the statement from the lady who was babysitting--and she was expressly uncertain and that may not have been the case.
It makes more sense that the first date (bottom right hand corner) is the date she registered rather than the date classes started which for extension classes was done by mail. You know that Winter Quarter Classes didn't start until the first week in January so you know the December 27, 1961 date for the Winter Quarter registration doesn't reflect her presence in class which didn't start until the following week.
On that basis, the 9/19 or 8/19 date probably would have reflected registration but not class start, whether night school or correspondence.
And the 8/19 date would be too long for Fall Quarter also. The 12/11 and 12/12 dates indicate the date she took the final (which might have happened for a correspondence course or a night school course); the quarter was ten weeks long--the partial thanksgiving week offset days lost for holidays; plus finals. So if the date was 8/19, it didn't represent a class start date.
Your suggestion that the start date really is 9/19 makes some sense; that's about when she might have registered for an extension class, correspondence or night school, for fall quarter.
I continue to doubt that she was physically present in Seattle in the fall of 1961--but it is certainly possible that she was. And for that matter, even if she made it back there by the 19th of August, that too doesn't exclude either the prospect that he was born in Kenya on August 4 (3 Seattle time and date) or the prospect that she got him all the way back to Hawaii on the 8th to register and then back to Seattle 10 days later.
But I continue to be pretty confident that whatever happened with the U of W, she wasn't physically in class in August and the fact that she was registering for extension classes fall quarter doesn't put her there then either.
The transcript form says Correspondence courses have a "C" suffix after the course number. Hers do not have the "C" suffix.
My understanding is that the baby need not be presented for registration in cases of birth not in a hospital. It was all done by paperwork.