Just started working on fixing up the APHE system and making the penetration calculations a little more realistic. What I did was I used a similar DeMarre formula as War Thunders that takes into account of whether it is capped or if it has explosive filler. That means that I had to change a little bit of the code but I got it working. I also added an APHE system that is fairly simple I think. It goes like this:

//Get the point where the shell hit the armor

Vector3 hitPoint = hit.point;

Vector3 hitPointLLos = new Vector3(hit.point.x, hit.point.y, hit.point.z + Llos); //This is the effective thickness of the armor so It spalls on the back of the plate after the shell penetrates

Spall(hitPointLlos, NumberOfFragments, Variance); //Spall code

Vector3 apheSpallArea = new Vector3(hitPointLlos.x, hitPointLlos.y, hitPointLlos.z + apheFuseDistance); //make a position some fuse distance further into the vehicle

Spall(apheSpallArea, NumberOfFragments, Variance); //Spall again

Explode(explosiveAmount, ExplosiveTYPE); //Explosive stuff

This means that shells can now explode after they penetrate armor (if they go through). I am working on making the APHE fuses damageable and depending on velocity, impact angle, how the shell deforms, and all that I will make it so that some shells wont go through. Once I iron out the system I will make another release!