The Tragedy of Macbeth (1971) - Macbeth's Prophetic Vision

I chose this scene because I was always curious with how the witches and this scene (4.1) in particular would be portrayed in a film or production of Macbeth. This isn't really how I pictured it in my mind, but I still think it is an effective production. I almost laughed as the witches were reciting there spell or curse...It kind of reminded me of a cult or some reason. The mirror part also stuck out to me more in the film production than it did while I was reading the play. The first thing I noticed was how Macbeth enters at the beginning of the scene instead of in the midst of the what the witches are doing. I've always been one to notice when lines are switched around in the film versions of plays.
So I guess that would be my question: Does changing the order of the lines change the play or the outcome of that scene? Also, is it an effective scene?