It's the same for me : against light amoured vehicles (BMP-2, Stryker, Bradley,...) HE is more effective than AP with BS (Not in real, HE is used against non armoured vehicle, infantry,etc...)
Forget the gun against MBT, not effective.
Of course in reality you can damage a MBT with a 30mm gun an with a lot of hit you can destroy it but you will lost a lot of ammo for a limited result.