There is an "easy" way to test this.
Offline, roll a yak9t (37mm with HE) taxi up to a ord bunker. Count how many rounds it takes to blow up the bunker.
Roll an iL2 (37mm with AP) taxi up to an ord bunker, count how many rounds it takes to blow up the bunker.
Note, can be point blank range, doesn't matter.
HE will do it in 2 or 3 shots.
AP will take dozen or more. (Because all AP has is kinetic energy, good for penetrating armor, poor for blowing stuff up)