Perhaps not an imported servant. Perhaps Mary Diton and Mary Dacon are the same individual. Dacon's son was in the service of John Whitledge in 1755.
(1) Ruth Sparacio and Sam Sparacio, Order Book Abstracts of Prince William County, Virginia (1753-1757) (McLean, Virginia: R. & S. Sparacio, 1988), 55, 70, citing Prince William County, Virginia Order Book 1754-1755:187, 264.
(2) John A. Cantwell, "Imported Indentured White Servitude in Fairfax and Prince William Counties, 1750-1800," unpub. M.A. Thesis, George Mason University, 1986, 63, quoting Prince William County, Virginia Court Minute and Order Book 1754-1755, p. 187, March 24, 1755.