Contrary to my previous post the affected defenses are deflection and reflex (not fortitude), and they can be increased by increments of 6 by quicksave>quickload and repeat, but only on enemies with shields, i.e. Mercenary Soldiers, Veterans, Sergeants, Warpriests and Commander Baelorin, suggesting a bug in the way the weapon-and-shield-style bonus to deflection and reflex is applied, but only to enemies.
.jpg.ce846aae50e732dc4985eb712252381f.jpg)
Sokatos's post in Caed Nua 'Looter' enemy with godlike armor? was marked as the answer