Yep, a clarification here would be nice.
I just did another test and even if I don't count the numbers in parenthesis I get:
MG20_82 API: 4
MG20_82 HEI-T: 5
MG20_82 MGesch: 3
That's 12 hits by 20mm cannon. And the Mustang kept flying.
Several times now I've seen a Mustang suffer a series of cannon hits and just continue flying as if nothing happened. I see detonations, puffs of smoke and then.. nothing.
Now I'm far from being a top gun but when in other combat flightsims I hit a fighter-sized aircraft with a good number of 20mm rounds it usually dies, not continues to perform all sorts of acrobatic manoeuvres.
ATM the 20mm cannons just don't feel right.