Why two more torpedoes per broadside may not be worth the weight

Would a 15,500-ton County-type cruiser with 9.2-inch guns have upgraded from quadruple to quintuple torpedo mounts?

It could, but the extra two torpedoes per broadside might be less valuable than using the weight for anti-aircraft guns or another improvement.

Moving from four quadruple to four quintuple mounts adds only two torpedoes to each broadside. The answer therefore asks whether that limited gain deserves the added topweight and space, especially when the same allowance might buy more 40 mm anti-aircraft weapons or another capability. The useful design lesson is to compare the marginal combat benefit with every competing use of scarce displacement.