I'm just wondering if this David Terrell and his wife Susannah actually named a daughter Susannah after her mother AND a daughter named Susan, which is basically the same name. There is no documentation for the connection or a list of their known children.
The two sisters have different info and husbands, so I don't think they're the same person and needing a merge.
I also see this David with two sons named David So I'm thinking there are some gedcom upload errors happening here perhaps