Thank you, following you, and you made a point that proofreading improves quality by correction of errors. But not only that, I believe that often better synonyms can be found and are replaced. Probably, it would be best to proofread one's mind before starting to write. I, for instance, just start writing without a plan, later proofreading removes errors but does not fix the basic structure or concept of my work. Good point you are making.