Adapt to Audience
You ask the grade/ education level of the author, but not that of the intended audience. I have a master's, but write for a newsletter intended for my 6th graders and their families.
I'd also point out that I checked an extract by Hemingway, and it pointed out that his use of language was unsatisfactory. His style didn't come up to scratch.
Frankly, the worst program of its type that I've tried.
I agree. The style suggestions it makes fail to take this into account and appear to work on the principle that the longer the word, the better the writing. Absolute nonsense,
I have a master's in science and perform TECHNICAL writing for engineering and technical purposes. In addition every professional, be it teacher, engineer, or lawyer can use a RESUME writing style as well.