Yes, there likely are differences country to country. In Canada there was a well publicized accident more than ten years ago, involving a Cessna Caravan carrying hunters, where though the passenger count was correct, the weighing of the bodies showed that the plane was taken off quite overweight due to each passenger being more heavy than the "standardized" weight historically used. The Canadian AC was issued to remove a pilot's excuse for not knowing or thinking about non standard passenger weights.
I went through this flying jumpers decades back, where the operator wanted me to fly "weight" by occupant count, but I objected, pointing out that most hearty pumpers, when equipped with 'chutes and gear, went well over the assumed (head in sand) occupant weight of 170 pounds per person. I stopped flying for them.
To my pride and delight, my local float operator has a scale just inside the gate, and everything gets weighed.