I believe that's how it works on the 600 too. I think there is a step missing here because iron bias must be accessed after a long press on the settings button once arriving recovery speed. Now once you have called up iron bias it will be constantly accessible in the settings menu unless you toggle it back to recovery speed by doing the long press on settings. So that may be where sandmartin and tennessee digger are at this point so then you can toggle between FE and F2 at will using accept/reject or toggle back to recovery speed using the long press.
Another note, you must set this up individually for each mode.