HS: Peter says the movie is finished only when they take it away. The movie’s never finished.

DG: Hmm.

HS: There’s just a point when they take it away, meaning that there has to be an end. You know, the studio says, “It must stop now. You know, you must stop working on this.” And that’s the way we all feel. There is that sort of delivery date, that goal, that moment when they say, “It must stop.” But you work so full on, and so completely dedicated to it to create it... because you also know you’re not going there... you know, you are creating this moment, say, of the Destruction of the Ring or describing the world of Lothlórien that people have read about for 50 years. And you want to make sure that your imagery of those worlds is as true and as real and as well crafted as you could possibly do it.
http://www.amagpiesnest.com/.../radio_interview.htm

Peter Jackson: The key point with the post production on any movie is the delivery date. And the delivery date is like the religious moment that cannot be altered and which the filmmakers have to hand the finished film to the studio. And from the end of October, they have enough time—just—to make the ten thousand copies of the film to get the film into cinemas all around the world.

Barrie Osborne: Even while we were scoring the movie and Howard had written his music, Peter was still cutting and recutting the film.
http://www.amagpiesnest.com/...s/ttt_appendices.htm