Dyslexic students at my university can request extended time for their exams, and it's typically 2x as much time.

Funny thing is that we give all 700+ introphys students more than that amount of time for every exam.
It's still not uncommon for a dyslexic student to request still more time.

As if anyone is increasing their score on an exam after sitting in a chair with no food for 5 hours. Whatever points you earn on that test almost certainly came in the first 2 - 3 hours. At some point, you just gotta admit defeat. At some point, it's a cruelty on our part to extend the time.