Special Rule for Stun Damage, Should lots of stun do some physical damage? Options

[Jizmack]

This house rule only applies to Stun Damage caused by regular weapons and unarmed attacks, like gel rounds and clubs. It does not apply to magical, chemical, electrical, fatigue, or otherwise non-kinetic sources of Stun Damage.

I need some feedback regarding the following house rule:
Every 3 Boxes of Stun Damage Also Causes 1 Box of Physical Damage.

For example, if a target is hit by gels rounds and after damage resistance suffers 7 boxes of Stun Damage, he/she also suffers 2 boxes of Physical Damage.

Using the same Armor rule for Physical Damage; if the modified Stun Damage does not exceed the AP-modified armor rating, then the attack will only cause Stun damage and no additional Physical damage.

Knockdown rules remain the same and do not take into account the additional boxes of Physical Damage.

The intent of this house rule is to make the so-called “non-lethal” ammo or melee weapons a bit more harmful and realistic.

I thank everyone in advance for any constructive feedback.