Just to add, many earlier content were created in previous Poser version which exhibit inherent built-in problems of their own.  These were correction factors because there were simply no other way to get around the issues.  One of the most common, active ambient channels for human skin.  Turn off all the lights and you have a model glowing in the dark.  And why was this done, to offset the lack of understanding about gamma correction and how it applies to linear rendering.