I would ask him/her about this. Seriously, Do it politely and respectfully. But try to understand if this is just about them and their personality, or some legitimate nuance to their work in that setting? Then try to figure out if this benefits the supervisor (their workflow, efficiency, time management, billing/productivity, patient access, clinical reputation, etc.), as well as the patients and referral sources you serve. Or, if it hurts them in some way? Or, if there is no measurable benefit by doing 14+ page reports? That would be interesting. Again, I am not kidding. "Consumer-oriented" report writing is something that needs to be taught/mentored in order to keep Psychological Testing evaluations relevant and useful in the current health care space.
Psychological assessment reports are only as useful as how the information is conveyed and disseminated to the audience. If you are babbling, hemming and hawing, and my personal favorite... trying to educate everyone and their mother about what each and every test you gave is and what is measures...you guys are wasting your time. No one reads this. Psychological assessment should not turn into a creative writing class. Nor is it a dissertation.
You want to help the referral source treat/plan treatment the patient. That's literally the only thing you need to be doing in a clinical exam. You do not have to fully explain or understand every single thing that is happening or has happened in the past. And you certainly don't want to "muddy the waters" with overwhelming amounts of information/background and/or too much speculation. A laundry list of 20 different treatment recommendations is not needed either.