Why did U.S. battleships need gunnery work with the Grand Fleet?

Why did the Royal Navy initially judge the arriving U.S. battleships' shooting so harshly?

The ships and crews had potential, but Congress had not funded enough ammunition and practice, so the squadron needed intensive gunnery training before it was ready.

The arriving American squadron received a poor initial British assessment of its gunnery and was sent to practice until it could hit targets reliably. The sailors and ships had potential, but Congress had not supplied enough money and ammunition for frequent exercises. British training tempo was far higher in the comparison given here, although the precise ratio is explicitly recalled from memory. The later Japanese belief that their crews were better prepared than American crews partly grew from observing this prewar and wartime training gap. The passage turns a joke about accuracy into a serious lesson about readiness funding.