Air, I was a gunner in a Lanc that night where I saw exactly what you described, except the attack started from a high 9 position. At 500 yds from the upper turret, both wings came off the F4U in their entirety leaving only the wing root/stubs. I continued to see pings hitting the corsair until it passed overhead. Simply couldn't believe that I was seeing a wingless airplane maneuvering as though it was undamaged.
If there is wingtip damage, I'd expect a visual representation of that. For HTC: What effect does losing a wingtip have on performance? Would the outboard aileron hinges be lost?
Moral of the story: Shooting one or two wings off does not guarantee a kill. It may not guarantee that the damaged plane is a neutralized threat.
Coining a Yogi-ism: A kill aint a kill till its dead.
MiG