When the genie engine duplicates a projectile. It uses the projectile’s own attack values.

So what actually happens here [with chu ko nu vs. siege ram], is that the projectile #510 has 3 pierce and 0 melee, whereas siege ram has 195 pierce armor and -3 melee armor.

Damage type 3 dealt: 3-195 = 0
Damage type 4 dealt: 0 – (-3) = 3.

Total damage dealt: 0 + 3 = 3.

Basically, each damage type is zeroed if they’re negative before they’re totaled. If the result is less than 1, it’s 1.

This is why no matter how much melee/pierce armor you add to a TK, a hand cannon will always rip out 10+ HP per shot, due to the damage bonus.

As an aside, unknown 20 in AGE 1.7 is actually the “default” armor value. In other words, unless you actually override the armor value, this is the value that’ll be used. It’s 1000 for most units, hence most bonus damages won’t work unless the target unit has the appropriate armor overridden. This is not the case for dire wolf, which has it at 0, which means a siege ram will do building damage and 1-shot it, funnily.