Deleted Scenes,,

With several deleted/extended scenes..be included in movie discussions? Should themes suggested by the commentary be included in discussions of the final movie? I mention this because of a recent comment amount David talking with Weyland(in statis) I don't have access to many deleted scenes,,and have no reference.. I only know the movie that was the final cut on DVD,, In this particular scene it is not clear who David is talking with..or what about. The assumption is that it is Weyland,,but in the movie it is not clear. Directors shoot many scenes with differences,,That doesn't mean that it's an acceptable version..just different.. I am just concerned as the 'extras' will be considered canon by site members ..and I am not convinced that is true. When a writer is writing a book..there are many stages of charactor development.. but tha is all they are just developments ,,before the final draft and release. Perhaps this true with the evolution of the movie we call 'Prometheus'.. I'll take the released version as the 'truth'..