Sounds like there's some kind of auto-level compensation going on. I'd go into the monitor options and turn off anything "auto" - auto color, auto level, noise reduction, black correction, etc. See if that helps.
Thanks for the advice. I guess its just the way it is . What a piece of $550 junk. Do not buy LG. Fortunately, the purchaser is sending us the receipt. It really is too bad. It was really thoughtful of mum-in-law, but I just can't watch different shades of black and call it entertainment.