69 is a little different. The body # is the confirmation number.
But still the same concept applies - the scheduler moved the orders around as needed. And a call from Estes caused the #1 and #2 cars to be moved forward in the schedule.
It is a confusing system from the outside. If you haven't worked in production, esp automotive, it can be hard to grasp. Once you understand it, then a lot of things start to fall into place.