This article, building on articles published in 1999 (NEHGR 153:340) and 2000 (TAG 75:16), points out that the Mary Farr who married James Mycall and later married Joseph Niles could not be the same Mary Farr who married Matthias Farnsworth.
The assumption that the Mary Farr who married James Mycall later married Matthias Farnsworth is the basis for assuming that she didn't marry Matthias Farnsworth until after 1659. Since it has been shown that these were 2 different Mary's, there is no such constraint on the marriage date to Matthias Farnsworth.