Hmmmm..I've never heard of any students needing extra time to take written exams...even when I was at RIT.....and I am profoundly deaf.
Based on your writing above, you seem literate, 53% is practically lightweight HOH..(and being deaf/HOH is absolutely no excuse for taking a written exam, IMHO) why do you need extra time to take an exam?
As for a 'certificate', if you are actually serious, the instructors are most likely asking for proof that you need special assistance to take exams. I would expect that for oral exams, but not written.
