Thanks Marty, I usually set manually to underexpose by 2 stops. I meant it is possible to really underexpose beyond limits of flash to compensate, even for the primary subject. While my original post was a mistake I did learn a few things. Thanks again.
"Cameras and lenses are simply tools to place our unique vision on film. Concentrate on equipment and you'll take technically good photographs. Concentrate on seeing the light's magic colors and your images will stir the soul." Jack Dykinga