If you had bothered to actually read the book (which it is abundantly clear you have not), you would have been aware of the copious footnotes made by Prof. Fehrenbacher, many of which are to Taney's personal papers and correspondence. This book is extremely well-researched and, perhaps, that is why it won the Pulitzer Prize for History.
As I remarked earlier, the book is not a Taney biography, although understanding Taney's peculiar social and legal views is an important aspect to understanding why he produced arguably the worst decision ever made by the Supreme Court. Whether one dates a case from the time it was filed (late 1818) or the time it was tried (early 1819) is wholly secondary to the point Fehrenbacher was making - that Taney's legacy, as somehow against the institution of slavery, is without foundation.
Try not to become lost in the minutia, again.
You wrote:
If there is a problem in dating the case from 1818, you can blame Carl Swisher, Taney's most literate biographer. The footnote for that citation reads: "FN19 ... On Taney's manumissions and defense of the abolitionist minister, see Swisher, [Roger B.] Taney, 94-98; Lewis, Without Fear or Favor, 44, 76-79."So again, your contention is that Fehrenbacher did not research the case, that he simply used the research of others, without any attempt at validating the information?