Writing a book is somewhat like baking a cake. The experienced cook knows when the cake is done, but it's difficult to explain how he or she knows to another person. So it is with a book or story. Each author has an inherent sense of when the story is finished, but no way to explain that sense to another person.
One of the most frequent questions I get from the house hunk is "Are you almost done?" Well... not yet. My current work in progress is close to completion, but not quite yet. This last week I wrote more than 10000 words, fully expecting it to be finished. But...not quite yet. So today I will write some more until that internal sense tells me that the story is complete.
That completeness, that internal sense is when we reach the point that our brain says “the end”. Do you remember when books used to actually have that printed after the last paragraph? Have you ever read a book where you thought those words would have been a great addition because you couldn't tell you'd reached the end? I read one that ended so abruptly I wrote to the publisher wondering why my download didn't contain the entire book. Imagine my surprise when I was informed that was the entire book!
I once sent a book to my editor, uneasy and irritable because I sensed it wasn't quite finished. Eventually, I retrieved it and added some more to the story, smoothing out rough spots, explaining things that were inexplicable. In edits, there were more additions. That book ended up nearly 10000 words longer than when I first submitted it. I will never again yield to the pressure to finish, finish, finish until my inner sense is at peace.
So the answer is: Not quite yet. But soon. Very soon.