Bob,
I'm guessing it's probably a matter of semantics. Perhaps when the ranger said that the overnight permit could only be issued for a particular trail, he meant what you said about it referring only to the TH entry point. However, I probably assumed that he meant not only the TH entry point, but the entire trail as well. I don't recall my conversation with him clearly enough to remember whether this distinction was ever discussed (I'm not sure it was). He just said that I could get an overnight permit either for one trail or the other. I probably drew my own more-restrictive conclusion as what he meant by that, which it seems was incorrect. Thanks for the clarification.
CaT