3kg TNT not being able to overpressure PZH2000

I play the vickers mk1 8.0 tank from UK tree. I’ve been having spalling issues on the apds shell against pzh 2000 such that my shot straight to the turret face that should pass right thru the turret hitting ammo and obliterating the tank only slightly yellows the ammo… I was like ok from next time I’ll just hesh it… Lo and behold… 3kg TNT of hest straigh to the side and hit hit hit… Not even any modules damages. I shot three hesh rounds into that thing and it was shiny as new. Heck I don’t even do enough damage to get an assist.