Man, I think if a guy cut me off and said I need to address him as "Captain", I'd turn around and walk off the plane. There's a guy with a major ego problem. I've never had anything close to this happen in all my years of jumpseating.
Anyhow, when I jumpseat, I just say "Hi, I'm a UPS guy looking for a ride" as I give them my ID and then introduce myself as I reach to shake the Capts hand. After that, you just kinda play it by ear.