Staff unit inheritance

Heres something I noticed when trying to find an A skill for my Veronica.

Staff units CANT inherit:
-Darting Stance
-Fierce Stance
Both of these stances have to do with offensive stats.

Staff units CAN inherit:
-Steady Stance
-Warding Stance
Both of these stances have to do with defensive stats.

And yet, staff units CANT inherit Bracing Stance. The stance which grants both a def/res buff. WHY? It was established that they can inherit the defensive stances, so why the fuck cant they inherit the double defensive stance?