Ignorant person here....
No attacks beyond T+60?
Example: I am in a bomber and drop first half of eggs at T+58, make a wide turn beyond T+60 and I cannot drop remaining bombs?
Example2: I am in a strike plane, hit my target, re-armed at a near friendly airfield and am back en route to my target, I cannot release those bombs or fire my guns on target if T = 60+.... BUT the enemy can shoot me down? (in this case it's literally not worth risking an airframe to MAYBE make it back to target before T=+60 eh?
AM I picking up what you're putting down?