Why ten or twelve twin mounts were proposed for Hood

Why estimate ten or twelve twin 4.5-inch mounts for Hood when the Hood Association suggests eight?

Renown received ten mounts, and Hood's greater space makes ten or twelve plausible. Eight is judged too few for a ship of her size and role.

Renown received ten twin mounts. Hood had more space, making twelve a plausible estimate, although ten remained possible. Eight appears low for her size and intended duties in this assessment. The total remains a hypothetical refit estimate.