Even though this is the wrong thread:
You are reffering to the APCR ability in the TD doctrine right? That only applies to specific vehicles and even if it did apply to the Hotchkiss I dont see why it would need it. The long barrel upgrade already allows it to penetrate everything so giving it further penetration is pointless. Plus its not like APCR gives it a dmg increase AFAIK. I could be wrong about that one.
And plus I dont think (or at least consider) the Hotchkiss is an area of eff weapon anyways. It kinda meh when it comes to killing infantry. Not like the PIV which has shells that kinda explode