How does UnitCrunch handle LETHAL HITS with DEVASTATING WOUNDS?

In 11th Edition 40K, LETHAL HITS became optional - you can choose to have critical hits automatically wound, rather than being forced to.

This creates an interesting decision when a weapon also has DEVASTATING WOUNDS, which deals mortal wounds on critical wounds (typically a wound roll of 6).

The Dilemma

If you auto-wound via LETHAL HITS, the attack skips the wound roll entirely, so it can never become a critical wound. But if you skip the auto-wound and roll normally, you have a chance to roll a 6 and trigger DEVASTATING WOUNDS for extra mortal wounds.

What UnitCrunch Does

UnitCrunch assumes you always make the optimal choice:

• When wounding on 2+ through 5+: UnitCrunch skips the LETHAL HITS auto-wound and rolls normally. Rolling gives you a 1-in-6 chance of triggering DEVASTATING WOUNDS for bonus mortal wounds, and you still have a decent chance to wound even if you don't roll a 6.
• When wounding on 6+: UnitCrunch uses the LETHAL HITS auto-wound. Since you'd need a 6 to wound anyway, there's no benefit to rolling - the auto-wound guarantees success.

Example

A weapon with S8 attacking T4 wounds on 2+. With both LETHAL HITS and DEVASTATING WOUNDS:

• Critical hits (6s to hit) skip the auto-wound and roll to wound normally
• Most will still wound successfully (83% chance)
• Those that roll a 6 to wound trigger DEVASTATING WOUNDS for mortal wounds
• The small risk of failing a 2+ wound roll is worth the chance at extra mortal damage

This optimisation ensures your simulations reflect the best tactical choices available.