Ok, getting hit in fuel tank and getting damage without a fire is quite fortunate, but: if the fuel starts leaking with incredible rate e.g. inside the fuselage, isn' there a huge risk of fire if you get hit again?!?
Inside fuselage there is lots of extra air availabe so a tankful of fuel leaking and any projectile entering the fuselage and able to hit a spark (not to mention incendiary, HE or tracer) would cause the aircraft to turn into a fireball or to explode right away, wouldn't it?
To be realistic a hit in fuel tank would not have much effect at all as they were usually selfsealing and inside the tank even a HE has trouble to cause any damage unless the tank is almost empty and there is a flammable mixture available and if the tank is not of "bladder" type. And if you see the fuel needle dropping rapidly and see a stream behind your aircraft that would mean you better not get hit again.
So IRL if you had a stream of fuel running inside the fuselage or wing and enemy aircraft attacking it was probably best to bail out right away or risk turning into an instant bbq.
-C+