I am a nonfiction book editor. Yes, we editors would like your cleanest draft to start out with. That means revising, rewriting, reviewing, and then backing away. You are eventually nowhere close to being objective. When you are sick of your work, that's when I want it. I also have a preflight checklist in my book, Cover to Cover: What First-Time Authors Need to Know about Editing, that helps you make those final tweaks before a professional edit.