POE Grade Boundaries

I've read a few posts but i'm a little confused and i've heard a few things from different people, many different schools have told them the exact past paper they're using and all they'd have to do is memorise to get full marks, whereas my school gave us a wide range and are specifically choosing difficult questions. I feel it would be unfair if we got the same average grade boundaries. Although I read it's unlikely the examiner will give you a different grade from what your school marked you but how would that work alongside the (middle east) region's average grade boundaries? (apologies if its a bit long, js stressed!)