With the Timings section, you can only control the simulated passenger boarding time but, you cannot change the length of the actual animations, which will depend on the number of baggage carts, which depends from the airplane weight.
The time it takes for the baggage truck to arrive, depends on the airport and if the scenery developer has correctly placed parking types of the "vehicle" kind, which are by default used to spawn vehicles from. If they are too far from the terminal, it might take a while for vehicles to arrive, and if there are none, a random parking will be used instead.
Of course, same for all things that seems "long" in the sim, you can use Time Acceleration.