How do I keep an 11 pm raid cutoff when the group is finally close?

At 10:54, our raid leader said, "That was our best attempt. One more?" I said yes, although I'd put an 11 pm finish beside my name when I joined the roster. The next attempt ended at 11:12. When I logged off, someone said, "Hard to build a team around a stopwatch."

I can play two evenings a week. I also open the café at 6:30 the next morning, and the bus won't wait because a boss had three percent health left. The group knows about the shift. But nine people had spent the evening learning with me, and replacing my role halfway through isn't easy. I understand why leaving at the promising bit feels worse than leaving after a messy attempt.

I've muddied my own limit by staying until 11:40 twice. The leader now treats 11 as the time to ask for an extension rather than the time I leave. There's a reserve player, but she understandably doesn't want to spend two hours waiting for a ten-minute turn.

What should I offer before the next raid: a real handover arranged in advance, an earlier last attempt, or my place on the regular roster? I want to keep playing with them without making every good attempt a fresh negotiation.