This page discusses in a bit more detail some of the more prominent changes which Weaver, Freeman, and Hayford and Sealts made.
Preface: In their 1963 edition, Hayford and Sealts omit the "Preface." They base their decision largely on evidence from the manuscript which shows that the note for inclusion and placement of this leaf was made by ELizabeth Melville, not Herman Melville.
Chapter 1: Hayford and Sealts here also disagree with the earlier editions in terms of paragraph breaks.
Chapter 5: In Weaver's edition, chapter five is not so short. He chooses instead to combine into a single chapter what in this edition appears as chapters five and six.
Chapter 12: Although Weaver omits this short chapter from his edition, Freeman inserts it. Hayford and Sealt, however, side here with Weaver and excise the chapter in t heir edition. Also, it should be noted that Hayford and Sealts eliminate all chapter eadings in their edition.
Chapter 13: Again, Weaver here combines chapter which appear separately in both Freeman and Hayford and Sealts.