I haven't fully characterized the issue yet, but after 5-6 flights, these are my observations.

You can select Agent Assitance for $0.00 during booking as a 100k. But that doesn't seem to stick. I needed a BP reprinted in DEN once and the agent (and supposed station manager!) insisted that F9 100K flyers do not get Agent Assistance for free. I said, it's right there on my booking -- I selected it. They looked, and said no.

On another flight, I paid more attention while checking in on the app. I think there was another button to select Agent Assistance for $0.00. I wonder if you need to reselect it during the OLCI process? I think I did, but I can't remember the result.

Any other data points regarding whether you select Agent Assistance during initial booking, or during online checkin?