Replacing Hood's 5.5-inch secondary battery

Why were twin 4-inch guns considered an adequate short-term replacement for Hood's 5.5-inch battery?

The 4-inch weapons offered useful anti-aircraft fire and common support, while the 5.5-inch gun served in very few Royal Navy ships and was being phased out.

Hood's 5.5-inch guns were capable weapons, but only a few Royal Navy ships carried them. Twin 4-inch mounts offered available anti-aircraft weapons while the uncommon 5.5-inch armament was being phased out. The panel distinguishes later reconstruction proposals involving 4.5-inch or 5.25-inch guns from what appears to have been an earlier interim 4-inch rearmament. The exchange weighs the merits of the old gun against the value of replacing it with weapons that could serve the anti-aircraft role.