Yep, I too am actually done with all drafting by the time the manuscript is complete.
I write out of chronological order. Sometimes I call it the "mold" method. A bunch of ideas and images and snippets grow to fill in and become a full story.
One thing nobody has mentioned here is that the nature of the story will affect how much planning (or rewriting) you need to do. Certain kinds of mystery, suspense, twist stories depend more on misdirection and laying the seeds of the ending in the beginning and all that. You can wing major parts of such a story, but you do have to know what you're setting up for.
An adventure or drama, though, only requires that you know the characters, their goals, and the setting, before you can set them loose.
I do disagree with Hemingway (as quoted up above) for most people, at least those with less experience, if you don't know where you're going, your destination is likely to be so mundane that your audience will see it coming long before you do.
However, once a writer has mastered his or her craft, that tends to not be a problem.