As far as i know, not really, unless you create your custom door object.
It is possible to modify that list of available values that drop down from the place I snipped above, but you would have to modify its GDL script. The other option is a separate label, which is maybe not the best. The one you already have set up will show on schedules, just not on plan.
What I've done above is to just select "custom" in the dropdown and type in my desired FR rating, then saved the door with all the settings as a favourite, and reused throughout the whole building.
AC14 through AC25, perpetual tinkerer