Hi,
I use to fly within P3D V3 aerosoft Airbus and PMDG. For those aircraft the payload, fuel and passengers are asked within the aircraft software. There is no update in P3D aircraft fuel and weights.
When starting boarding only a Van approaches with the passengers even when there more than 6. I think it is a nice idea that GSX takes the facts from the airbus and PMDG values to send the correct busses and luggages. (When I watch the loading of the luggage I realize that 4 luggages remain on the trolley. Normally all the luggages are loaded.