From my experiences with using Manual chaff and flare release, the F-16 is incredibly bad at spoofing heat seeking missiles. The flares release too slowly and when they do manage to release, only 1 comes out. If a heater is fired at a F-16 from less than 5 miles, the 16 can consider itself dead meat.
Is this modelled accurately? It has gotten to the point where I don't even want to fly the Viper until this gets fixed. Even when using the most effective tactics, I.E. Engine to idle and jinking with flare release, I only am able to evade 1 in every 6 missiles fired at me, whereas in the F/A-18 or F-14, doing the same tactics, I can evade almost every time.