From chapter 10 of “The Girl on the Stairs”, this is what a Jim Leavelle report dated 2/17/64 says Adams told him on that date:
When the President got in front of us I heard someone call him, and he turned. That is when I heard the first shot.
That is one of her alleged statements and we don't know if Jim Leavelle wrote down verbatim what she said or recorded it. It is apparent that Victoria Adams did not review the statement. You are placing a lot of weight on Leavelle's recollection, uncorroborated, that she actually said "that is when" in relation to JFK turning.
Dorothy Garner, who was standing at the same window with Adams said:
"I recall that moments following the passing of the Presidential car I heard three loud reports which I first thought to be fireworks but only seconds later realized something had happened on the street below although as the time of the shots, the Presidential car was out of view behind a tree."
In Adams' WC testimony she said her view of JFK was obstructed when the shots were fired:
"Miss ADAMS. And from our vantage point we were able to see what the
President’s wife was wearing, the roses in the car, and things that would attract
women’s attention. Then we heard-then we were obstructed from the
view.
Mr. BELIN. By what?
Miss ADAMS. A tree. And we heard a shot, and it was a pause, and then a
second shot, and then a third shot."
By the way, if you accept Victoria Adams' statement to Leavelle, why do you not accept her statement about the shot pattern: "we heard a shot, and it was a pause, and then a second shot, and then a third shot?"
Why should your favorite accounts be taken as more credible than Adams’ account?
It is not about taking "favorite accounts". It is about examining all the evidence and fitting it together. The early missed shot/second shot SBT does not fit large bodies of consistent, independent evidence. One has to ask: how is it that so many witnesses independently recalled that the same consistent things?