I think the questioners are right that I could have made more in the text of the ways in which the author cannot possess the work. Not just in the sense that the work once public is open to foreign hermeneutical strategies, though that is important.
What I was trying to say was that the author cannot possess the background, the facticity, the foundation, if you want, of the work. There is no graspable foundation. We cannot encompass our own birth, the world, language, sending or gift, or the meaning(s) of being we find ourselves within, to use Heideggerian turns of phrase. The author cannot possess the work even before it is exposed to the hermeneutical action of the other. For the work was never private, just as the author was never a single individual.
I talk about that in Socrates when I talk about the discourses that come before and around argument, but I could have done more to embody this in the text.