When I place orders for a customer (a retail order), I have to give it a priority code from 10-19. Orders for store inventory (a stock order) gets a 20-89 priority code. Priority codes tell Ford which order the dealer wants them built in, from lowest # to highest. Cars only compete against the same model within the same dealership, so I can put a 10 on a Mustang and a 10 on a Focus, and they don't affect each other. However, a 10 on a Mustang V6 trumps an 11 on a GT, so you have to compare your own priority code on a Mustang order against all the other Mustangs ordered at that dealership.
The regional offices can pull an order ahead of all others for that dealer by assigning an "01" priority code. This is usually done for specialty vehicles and/or when a customer calls in to complain about an order taking too long.