Unexpected - Stalin fires HE when AP available

[PoorOldSpike]

My panzer got LUCKY plain and simple, because 9 times out of 10 a Stalins HE hit would have killed it..:)

I just ran a test a few times (pic below) by lining up 15x Stalins and 15x Pz IVH's facing each other, then stripped the AP shells from the Stalins, leaving them with HE shells only and let them shoot it out without any orders from me.

This pic shows the carnage, the Stalins HE shells ripped the panzers to pieces no matter where they hit (turret/ upper hull, lower hull) and only about 1 in 10 Stalin HE shots scored partial pens/flakings/ damaged gun/ immobilising hits.

By the end of the turn ALL 15 panzers were dead, for the loss of only 3 Stalins (I let the panzers keep their AP shot, most simply bounced off the Stalins tough hide)

PS - I ran the test a couple more times but gave the Stalins their AP back, and the result was the same, 15 dead panzers, 3 dead Stalins.
All the Stalins fired AP only even though they had HE shells on board.
So as I say, my panzer in the earlier pic was lucky to only take a HE flaking hit, and lucky again that the flying flakes never killed the crew, how lucky can you get?
(However it doesn't explain why the Stalin fired HE in the earlier pic, maybe it was because the Stalin was low on AP shells so the crew decided to fire HE because they knew it was very good against panzer IV's)