Anytime I make a service appointment for a warranty issue, I arrange a loaner vehicle (typically F150 crew cab) before I drop off my Expy to avoid any waiting. Perhaps that strategy would simplify things for you a bit if your dealer is reasonable to work with.
I tried to make arrangements for a loaner before I get my Expy repaired but the Ford dealership claims the wait is 5 weeks before I'd be able to have a loaner. My Expedition now has a leak from the Vista Roof after the dealership repaired it. I have to keep it garaged until Ford Motor Co give authorization to allow a warranty whole Vista roof replacement.