Self sealing tanks were surrounded by a rubber material. When the fuel tank was hit, the leaking fuel made the rubber swell and seal up the leak.
If a hole is big enough for a self sealing tank not to seal reasonably well chances are that the damage is significant enough to render you unable to draw any fuel out of the tank quite soon one way or another, regardless of where whatever struck you struck IMO.
Airflow wouldn't be able to suck fuel out of a tank if the fuel doesn't reach the level of the hole. Fuel does not levitate.

Having different levels of damage modeled would be really nice though! When you hear that godawful "pellets-on-sheet-metal" sound you should have a reason to check the effect of your control surfaces... and checking does NOT mean to look out the window to see if your aileron is still there or not AH style. If this is modelled somehow albeit not visually, I have thoroughly failed to notice it.
Cheers,
/ft