I'm on a saver award ticket (IN) SFO - LAX - SYD. The nonstop SFO - SYD on the same day is PZ1 IN0. But after check in, the app shows me and my non-status companion the option to confirm SFO - SYD in C for $0. This surprised me as I thought IN would have to be greater than zero. I don't fully trust the app so I called an agent -- they tried to make an exception to put us on the flight but in the end could not without 120k additional miles (to go from IN -> JN).

Should I try to do this via the app? Or do I risk it "undoing" itself shortly, either automatically by the system or manual review. Thank you.