How long were mixed cruiser batteries defensible?

Could mixed main batteries remain justifiable after 1905 because of fire-control limits?

Briefly; fire control, inherited doctrine, and foreign practice explain some lag, but they do not justify indefinite delay once unified batteries were workable.

Contemporary fire control still complicated long-range shooting, which could justify allowing designers until about 1908 to abandon mixed batteries. Technical limits, inherited doctrine, and the fact that other navies continued building them explain some persistence. That allowance was temporary rather than absolute. Once a navy could build a unified heavy battery, continuing with multiple calibres sacrificed fire control and logistics without a compelling operational return.