Nope, just to incoming lethal hits. Because foes can’t block timed hits, the provision to stop lethal hits does not apply to them. Basic logic for timed hits:
If you are attacking, opponents can’t block timed hits so lethal damage will always be lethal damage. If timed hit takes nonlethal damage into lethal damage, it will kill.
If you are defending, timed blocks cannot block an attack that would be lethal BEFORE a timed block occurs. If an enemy is projected to hit for 15 damage and you have 15 health, a timed block will not save you. However, if an enemy is going to double you for 10x2, and you have 20 health, a timed hit block on the first strike will make it so the second hit will not kill.
Hopefully that clarifies things. Also, be careful if implementing fixed growths (there aren’t any in the game). I use a lot of global flags for NG+ mode and EF could cause things to be affected, can’t remember if it is a conflict or not.