Almost everybody contemplates, scrutinizes, and thinks about revising their work. In the case of a musical score, it's the latest revision that the composer holds in highest esteem as a sample of their best work. It's that seemingly insignificant additional touch (photo) which reveals the originator's cleverness, if not genius, and elevates the work to an even higher level of artistic perfection. Removing something very minor from the soup recipe and replacing it with just a minute pinch of something else like common table salt can make a world of improvement in how it comes across. In deference to the composer therefore, we should study and learn only from the latest version of the score, the one which contains the writer's finishing touches [See menu bar, Free Stuff].