So here's the thing about the jumpseats and gate agents. They think they have control, but do not. The Captain determines who gets the jumpseat, and has the guidelines to follow. All jumpseaters who ask to list are given a flight deck access card, regardless of if they are OAL or own metal. That gets you down the jet bridge whenever you find is the appropriate time to go. You then politely ask the Captain for a ride and they determine who gets it. It is not up to the gate agent, or a computer. If a gate agent gives you a hassle about this, ask them nicely to pull up "jumpseat" in "wingtips" and if they still don't, contact your jumpseat committee. Additionally there is no 30 minutes cutoff, that's FA stuff.

Sorry you got hosed.