I was on there just before Xmas and when they handed it to me (I had to collect it from the coffee shop - not delivered to the room), they said that it was one punch for a small, two punches for a medium.
I never actually tested that, I just stuck to small coffee's after being told that. It is good value at 1-punch per coffee, poor value if they are double-punching for the med/large that is only 50c more to purchase.