The manual is very confusing, using somewhat different terminology. Try adjusting “Setup” as described on page 8 of the manual. “Setup” usually refers to the 7.5 IRE offset used on US NTSC video. But I think for the BVTBC10, “Setup” = “Brightness”.
In this manual, US NTSC offset is called “Pedestal” which is set per the instructions on page 14.
The page you’ve referenced is discussing the serial data communication protocol used to adjust the unit remotely. Why here they refer to contrast and brightness rather than luma and “setup” as used for direct control, I have NO idea.
Hope this helps,
BW