How formal is too formal?
When a reader has to work to extract the meaning. If a shorter word says the same thing, use it. Utilize instead of use, and prior to instead of before, add nothing except length, and experienced graders read them as padding.
This comes up on Academic Writing Style, where it is answered in the context of the work itself.
Not what you asked?
Ask us the actual question
Send the draft, the rubric or the score report with it. You get a real answer and a price before you commit to anything.