The light-spear gives only to defense, so perhaps that's why it didn't make much difference regarding cavalry deaths. The spear_bonus_x on the other hand gives to attack, so again that should explain the difference.

I advise that you don't charge the cavalry into the infantry if you want to getnot seem like a big difference, but it is if you try to be precise. accurate results. Charge bonus comes into play (even if you have set it to 1) and various other stuff, like the mass of the cavalry that disrupts the infantry formation, and can have an effect on the battle outcome. It might not seem like a big deal, but it is if you're trying to be precise.

Since we're on the topic, have you run any tests with short_pike? I never find the time to them myself... :)