Why did County-class refits cut down the quarterdeck?

Why were County-class cruiser quarterdecks cut down during refits when cabin space was valuable?

The change improved boat handling and stern access while reducing aft weight, even though it sacrificed enclosed space.

The question points out that accommodation was already scarce aboard County-class cruisers. The cut-down quarterdeck made boats easier to launch and recover. It also created more useful working access at the stern. Removing weight aft could help the ship's speed. The refit therefore traded enclosed volume against boat handling, stern access, and lower aft weight.