1. Why do some cavalry have a 9 spear attack with low lethality (like Italian)? Also do such cavalry have a better attack than those with 4 AP and high lethality?

2. Why do celtic longswords have so high lethality while the gladius shortswords have little? I have read in Vegetius that the stabbing wounds in chest were the most lethal, while a slashing attacks did not manage to pierce some bones in the body.