Do you want the fader at -12db or the gain ?
what if you add audio recorded at -24db, should it then still reduce the level by 12db?
Or is it intact a level setting that scans imported or recorded audio and automatically adjusts the gain to -12db peak ?
Sorry for asking, just not clear to me.
If that was my mixing approach, I would simply select all audio and normalize to -12db, done.