Please give a glance to following picture:

I had previously hit this guy with my 20 mm shells, causing damage clearly visible in above screenshot.

The bandit kept flying and performing evasive maneuvers. BTW, I checked in FMB it was an average pilot.

I know Messerschmitt wings are made of Krupp's steel and he's of aryan race , but still wonder about inconsistencies between damage shown and how they affect actually flight model.

Happy New Year!
GB

Yes, it can be frustrating can't it. One mission a split second burst kills them, the next it seems to take multiple hits/saddling up. They do experience problems flying from damage, esp if you hit a wing-tip there is a good chance that they'll go into a spin when they try to turn (nice cheap victory in ammo expended). Looks like the damage in your shot is distributed between both wings, so it would just increase overall drag.