There are some paramteres that are the same and the same colors and HDR Multiplier can be used. Such as Diffuse Specular, Fill, etc. I did it but I have set the day lighting used for the Terrain set, then for the specific region copied the parameters of the lighting I want. Not sure if there is a difference though. Since the lightings I use are Tyrador and Ulaan, I can't see if the region uses e.g Ulaan or is still Tyrador when the whole terrain is set to use Tyrador. I can't make a difference.
P.S I do the lighting values for region pasted when Tyrador is selected in Window - Lighting, which is the lighting the map uses, I dont click on Ulaan.
Setting regions w diff lighting is needed if you want to do say Interior with normal lighting, Night lighting outside seen from inside through the window, as I have such maps. Thanks though, I got it now how it works.