The person who lands the most rounds on the target gets the kill when it dies. Otherwise you get an assist... even if your shot was the one that killed it. Just the way it is.
Anyway... back to the ORIGINAL question:
Yes... B25H's carried 5 AP rounds. And to point something out... you have to get the round INTO the tank to kill it... hence the need for AP. HE just explodes on the surface... although with the right angle and placement, you can get a kill on a tank with HE. The HE rounds on the 25H are BEST used for softer targets (Light armor, Flak, buildings, barracks, ords, ships, etc)
Would I like to see them on the 25H? You betcha. Will we get them? Who knows.