Sounds odd, right? Reading your manuscript backwards does not mean the last word, then the next last word etc. It means scrolling to the end of your manuscript and reading each sentence. If we take a work in progress by Jayne Thornber, we can show you what we mean.
Excerpt
Behind her, another fossil sat. Gifts to herself, from herself. Her grandfather worked every day of his life running the damned workshop. Every day until a week ago. She’d pulled her head from under the bonnet of the Mustang, calling for her grandfather to give it a go.
Here we would read, “She’d pulled her head from under the bonnet of the…” work on that sentence making sure each word was required, and the intent was understood. Then we would move to “Every day until a week ago.” and realise that wasn’t a sentence (which is much easier for our editor to do when there is no context to the sentence). Fix that phrase: “Her grandfather worked every day of his life running the damned workshop—every day until a week ago.” And move on.
The power of removing context from editing is substantial.
Again, you can pay an editor to do this for you, but you are becoming a better writer by learning how to do this yourself.