Why a nominal 3,000-ton postwar frigate would grow

Does a 3,000-ton-plus limit make sense for a postwar Type 15- or Type 16-style frigate?

The navy might call it a 3,000-ton frigate, but the completed ship would probably approach 4,000 tons after additions.

Postwar conversion and escort requirements made a strict 3,000-ton ceiling difficult to hold. Designers could announce a 3,000-ton frigate while successive equipment choices pushed the completed ship toward 4,000 tons. Sensors, weapons, machinery, and service allowances accumulate after the headline target is set. Nominal displacement limits rarely survive contact with a fully equipped warship.