Thanks for posting this! I've been struggling to write my first novel, and I'm interested to see how I score with this.
Of course, when you're writing, many times you break the rules. At times grammatically incorrect dialog, for instance, scans better. You might leave a subject off a sentence, make the reader hunt around for it. You might make some sentences difficult in order to contrast them with freely-flowing sentences in the space afterwards. You might create long, difficult-to-read sentences punctuated with short declarative ones.
Wonder how this tool is going to know any of that?