I am wondering if my experience in deciding where I get my parts is different than others. it seems to me that the service techs are who decides in most cases, just who we order parts from.
Most of the time the dealership has an "after-market" supplier who is somehow connected to the OEM, but if I requested or just gave a PN attributed to some other source, the parts department has no problem with ordering from that source, (and rarely asks twice).
Where you work, is it the parts department, the dealer principal, the customer, the Shop Foreman, Service Manager, the tech, or just who decides what source your parts are from.