Surely this isn’t that hard?
A big flying school with a set price for your course shouldn’t charge extra for exams.
A small school absolutely should. Why should the 60 year old PPL getting a flight review pay higher dual fees to subsidise an instructor supervising your RPL exams? To say it’s zero cost to run an exam is absurd.
That same PPL holder will use the toilets, pens and computers hence they’re rolled into the rate everyone pays.