I hold a Masters Degree and have written numerous papers and essays. I edited my oldest son's papers as he worked on a degree in History. I understand the difference between there and their and two, to and too. I look for spelling, grammar, structure, and does it make sense. I read many stories where the author is thinking faster than they can type. I look for out of place words, does the content make sense, flow and pacing. I do not rewrite your story, I try to eliminate distractions. I hate reading a story and see consecutive words or change of gender in mid paragraph. I am retired and not constrained by work or other time issues.