You still do not understand. Cell Light is a BOGUS CONTROL. It does NOTHING USEFUL. Samsung themselves admit this if you get the the right people to talk off the record. The only right setting for Cell Light is to set it to 20 and LEAVE IT ALONE (set to the highest setting, earlier models topped out at 10 I think).
Cell Light exists only to fill the slot taken by the Backlight control in LCD TVs. It is convenient for Samsung to use the same menu structure for plasma and LCD TVs so they "invented" the Cell Light control to add something other manufacturers don't have, even though it does nothing useful.
You set how bright white is with the Contrast control and you set the black level with the Brightness control and you leave Cell Light alone! Before there was a cell light control, plasma TVs (all of them) operated the same way they operate with Cell Light set to maximum.
You are doing all kinds of messing around that would be 100% fixed with proper calibration using a meter and calibration software. Anything else you do is just guessing.