agree, but its where the vehicle sits and the way the weight is spread over the front and rear axle, the payload of a LWB and MWB is the same, but in the real world and VOSA world, the LWB will be legal to carry more because some of his payload is transferred to the front axle keeping less weight on the rear axle, the long overhang will also be like a leaver putting more weight on the rear and less again on the front axle, it gets very complicated, but a LWB is a better option