I'm not sure this will help much, but ask yourself the question, did the result -- the event described in the result clause -- really happen? If it did, it's actual result.
Natural result: "He was so brave as not to flee." He was so brave by nature that he would never flee [e.g., even if he had met Achilles in battle, though he never actually did].
An actual result clause would be "He was so brave that he did not flee [e.g. when he met Achilles in battle]."
Dr. Phillips was my second-year Greek teacher. The book dates from the 1950s, I think, which to me doesn't seem that old as these things go, or didn't when I was taking the course (1961-2). Dr. Phillips never seemed very enthusiastic about teaching teenagers Greek. My first-year Greek teacher, Dr. Phillips' colleague, used the much older Crosby and Schaefer, which always seemed like a much richer and more stimulating book. At least it went to much greater efforts to retain the interest of a 14-year-old.