Hi farmers
Raul has just added a note to point 6 b) in the main post:
b) When unloading a train, if you have at least 3 trains dispatched or ready to unload with 10 cars each, you will earn an extra bonus of 80% of the products delivered by that train.
Note that any of your trains have the chance to earn this bonus, not only those with 10 freight cars.