ToME: the Tales of Maj'Eyal

https://te4.org/wiki/Effect#Cross-tier_Effects

Off-balance occurs when a physical talent hits, and the attacker's Physical Power is in a higher tier than the defender's Physical Save.

https://te4.org/wiki/Character_sheet

Physical power measures your ability to deal physical damage in combat. When you use Physical power to inflict temporary physical effects on an enemy, every point your opponent's relevant saving throw exceeds your physical power will reduce the duration of the effect by 5%.

question:
Off-balance will grant to the defender when the attacker has higher tier of physical power than the defender's tier of power save. But how could the defender using physical save exceed attacker' physical power to reduce the duration? It seems like contradiction.

Why can't a defender have higher physical save than an attacker's physical power? I'm not seeing any contradiction.