I don't have a Thomas Motley in my lineage. But I might be wrong. What I have for my lineage is: Grace Motley 1906 - 1982 (my grandmother) to Charles Motley 1855 - 1929, to William Motley 1801 - 1860, to William Motley 1776 - 1871, to James Motley 1730 - 1783, to John Motley 1699 - ? , Richard Motley 1668 - 1714, to Robert Motley 1623 - 1675, and lastly, William Motley 1591 - 1638.
I have only verified through James Motley, thanks to you, so far. So the rest of the line is still a maybe. Got most of the info from familysearch and ancestor.com. But from what you have said, it could very well be all wrong.
I don't think the Motley's were educated with writing, so you are right on the money when you said who really knows the correct spelling of the names.
The Motley seem to be very prolific!!!! Are we related?