If you're on the final approach course and inside the PT limits...
why not?

That's fine, but my point is that the 10 nm is given to you on the
profile view, not the 10 nm ring, which has nothing to do with the PT.

Trivial distinction?

I don't think so. We had an approach that had no PT, yet some
instructors were teaching that an a/c could descend within 10 nm of
our FAF, because of the 10 nm ring.