Good point about the avid system. Didn't Lucas try to talk Spielberg into editing Last Crusade digitally rather than by cutting the film? Another thing to remember is that if part of a scene was cg "enhanced," LFL still had to scan and restore the whole frame. And we know they did scan the whole film, how would they have known which parts would be changed and not needed? There was an article posted here about the Death Star run where they mentioned "fixing" one part and then Lucas wanted to redo the next shot that was most dated.