William "the Immigrant" Thornton, IV "the Immigrant" - Need Curator Assistance

This William has ended up with two sets of parents. From what I know of the line, I believe Frances Robinson and her husband WilliamThornton II are the grandparents, not the parents. At least that's what shows in trees on Ancestry. William Thornton of East Comb (Thornton) III and Bridget Marshall seem to be the correct parents for this William IV. Thanks.