First thing, after selecting "request Boarding" all the vehicles appiers around the Position, Stairs , trucks ...
But first the Baggage Trucks are driving away .... hehe where are you going :-)
As i see on the Airports the Trucks are Loaded and start loading directly.
Can that be changed, that the Trucks are loaded and do not drive away first , load the baggage and then come back ?
This is normal, not a bug, and has been like this since GSX has been released in 2012. The loaders that starts on a parking, are the ones which will be used for Deboarding. If you call Boarding, loaders will come from far away, so the ones that were supposed to be used for Deboarding will go away.
Second thing, it seams the sequence is a little bit wrong. During the loding of the passengers the Fuel Truck arrives. Can that be correct? I think first shuld the Fuel truck arrive and after refueling the loading of passengers should start, not before refuling is completet. Correct me if i am wrong.
Of course is correct. The whole point of allowing simultaneous servicing is to shorten turnaround time and, since refueling is the service that takes most of the time, it arrives first.
Also , i think you know where your vehicles are located during the Sequence, but the Service Trucks drives over the Fuel Truck
They usually don't but, as explained so many times on the forum, vehicles are not aware of each other (you assumed this, but it would cause a big fps hit if we had each vehicle to check the position of all the others, at each frame), so we can only play with sequence of operations and time delays, which won't guarantee this will never happen.
Also, some times the Baggage Truck drives under the Wings of the B7378 and i think tht is not allowed in real.
As explained so many times on the forum, depending on were you parked, how the airplane is configured, how the parking is made, how the scenery is made, how the AFCAD nodes are made, how the vehicle is made, how many carts it has, how long it is, ALL OF THESE have an impact on the path chosen.
What you can do, is customize the vehicle starting positions but, again, there's no guaranteed they will always do a realistic path under ALL the other conditions.
--> i am using Prosim737 and have no control about the Pax weight, which is a bit too less. So GSX loas all the Time a incorrect amount of Pax.
Which is why, you have the option in GSX to DISABLE the "Estimate passenger number", so GSX won't try to guess their number by the weight, and will just ASK you to enter the exact number of passengers on board.