It's a new kind of book. Three different versions of each event and the reader can pick the one he/she wants to believe.
You make a great observation. However, I suspect that the reason the publisher allegedly did not get the manuscript until this late date is for that very reason. Hillary had to make sure each of the thirds were consistent before she dare release it to the publisher. Also keep in mind that Hillary's "memories" are time-sensitive to the present. She may have had to edit up to the last minute, based on what she said in some speech 2 weeks ago.
A final cynical, but understandable explanation of Hillary's out of character attribution to ghost writers, co-writers, collaborators or whatever. When inconsistencies show up, she can blame them. She was too busy being the best Senator she could be.