Now that I see the VIN’s you are referring to, I understand.
Your reference to the last eight and seventh # of VIN was throwing me off.
If you refer to the VIN info. here:
Counting the VIN #’s from the beginning, the N is the tenth digit, referring to the model year. N being 1992 or 2022.
Next digit, being digit # eleven refers to factory ID. In first example being 1 (not I) refers to the Oshawa plant in Canada, scheduled to begin building trucks in early 22.
Second example with F as digit eleven refers to the Flint Michigan plant.
Obviously there are currently many issues with production and delivery so I can’t answer your question of why trucks from one plant are arriving before another but hopefully bringing another plant online to build trucks will help them get caught up sooner rather than latter.
At least your info. cleared up my confusion over your reference to VIN information. Hope this helps.