There are several other discrepancies between the two versions which are addressed in «Who Wrote the Bible», which was written
by Richard Elliott Friedman, a
biblical scholar and the Ann and Jay Davis Professor of Jewish Studies at the
University of Georgia.
I'd refer you to «Who Wrote the Bible»
by Richard Elliott Friedman, a
biblical scholar who is the Ann and Jay Davis Professor of Jewish Studies at the
University of Georgia regarding the authorship of the flood story in the Bible, specifically pages 53 to 60 in the «The Story of Noah — Twice».