Razor think it is optional for the defender to commit interceptors. If you dont want to give extra protection to your factory, or port, or airfield, then just dont do it. Let the facility’s AA-gun defend the facility. Nobody force you to commit interceptors. It is the defender’s decision.
Razor also urge you to take in account that the dogfight between escorts and interceptors are one round only. And after this one round, all fighters retreat from combat. No escort fighters will be exposed to AA-fire.
If the defender commit 2 interceptors, that defend on 2 or less, it is not very likely they will hit anything.
In this case the attacker may commit 1 escort just to absorb a possible hit, so his bomber get through.
If your territory are both attacked and SBR’ed at the same time, it is better use of the fighters to defend on 4 or less in multiple rounds, than defend on 2 or less for one round. Butt Razor not sure, must figure.