No. You acted properly at the authors request. The ball is in his court let him initiate the fight. Be apologetic after all you were in the wrong, but do not give the impression that you believe there may be a case for compensation. Don't put any resources into this unless you are forced to.
I’ve really slobbered all over him both on the phone and in email. This is a rare time when I genuinely offered an apology. I really was sorry to have wasted his and my time over such a matter. I really appreciate your advice. Are you an attorney Realism?