[jp10]

Not to argue against the many fine points made here, but in the decade after WW1, during the 'Infantry Tank verses Cruiser Tank' debates, the AP function of the gun was more for an anti-material role (especially bunkers) than shooting other tanks. Some designs had a small bursting charge to explode if the round failed to penetrate.
My point being, with these early small bore or infantry support role tanks, maybe the AP function should be considered for short range shots at fortifications and light vehicles, not tank battles.
I don't suppose the ability to 'turn off' selected weapon systems on a unit could be tweaked to allow an ammo type to be not used, allowing a player to select a particular ammo for whatever reasons they foresee?