B-25s soak up way too much damage. I've raked one 2x in totally lethal attack runs as it was taking off while I as in a Fw190A8 with 4x20mm. I've also landed 3x 37mm hits from a P-39Q in one before, also when it was trying to up from a capped field. Reviewed the film, all 3 hit, one even hit dead on in the port engine, and all it had was an oil leak.
In the Coral Sea scenario I sat behind a B-25C after unloading my cannons in several passes, and sat at 600 yards dead even. He was in the bombsight, he didn't fire back. So I unloaded over 1000 7mm machine gun rounds into the same square foot of wing root. Now you may say that "oh, these guns are weak" but I sat there unloading in the same spot. By sheer amount of lead on target alone I should have snapped the wing off, got a gas leak, gas fire, anything. Instead he dropped his bombs (I think) and pulled up. I broke off because I was now 300-400 yards out and he was waking up to my presence.
I eventually got the kill from sheer bullets on target as somebody else finished him off, but I did no real damage. It's not like I'm a bad shot (well, I wasn't, I am NOW, since I haven't been flying as much, but at the TIME I was a very good shot) and it's not like I'm scattering rounds from wingtip to wingtip. I mean steady stream of bullets all in one spot for a long time with no results.
B-25 is a damage sponge. IMO it's not right, but hey HTC's not going to take my word for it.