Flashless cordite and the size of the charge

Was the newer flashless cordite as energetic?

A modest reduction in energy per unit could be accepted to avoid revealing a ship at night, with a larger charge compensating where gun dimensions allowed it.

Flashless propellant reduced the risk of revealing a ship's position during night firing. A slightly lower energy per unit could be offset by increasing the charge. That compensation had physical limits because more propellant occupied more space in the gun. The one-percent reduction is an illustrative example, rather than a measured specification for a named cordite grade.