Nagato's true speed and the treaty battleship balance

What might the treaty powers have done if Nagato's true speed had been known?

The proposed response is four new British ships, four American completions in total, and probably two Japanese completions.

Knowledge of Nagato's true speed might have produced a negotiated increase in permitted construction. Britain could build four new ships instead of two, giving it a full squadron. The United States could complete four in total, including two additional ships expected to prove faster. Japan would probably be allowed two completions under the proposed arrangement.