There is definitely something amiss within the game.  
I am experiencing like the OP stated, many pw's, fires, loss of tail and wings all from 1 to 2 hits, particularly 20mm.   The other day I was hit by a C205 and my Dora after bailing out had both wings, its vertical stab, rudder, 1 horizontal stab, oil hit and a pw from what was a few hits.  Had to laugh. 
Who else is getting many fly through ack, "ping" then your in the tower?
Today flying a Spit16, 1 hit from an LA and my right wing departed. 
Yesterday in a 190A5 flying over a town I lost a horizontal stab, although I heard the ping, there was no tracer on the film.  Then as I opened fire, my engine burst into flames and I cannot find a hit from enemy fire on the film? 
The damage for the 20mm especially seems to have been increased but I think maybe a little too much. 
NG <S>