LT-15 T28 HTC, tricks? tips? coping methods?

Got the StuG IV mission once upon a time on Prok in my M41 (over 5000 dmg btw), haven't come even a lick close to that since. I'm going nuts.

Tried passive. Tried active. Tried hero runs at the start. Tried sweeping runs late game. Tried dealing ass loads of damage. Tired praying to SerB. NOTHING WORKS.

Is this serious a roulette? Because it sure feels like it.