We going to need visual representations for clarity.  Testing out this feature for the first time recently on an image I have been working on in PoserPro and I have found that activated IDL with tone mapping set to 2.2 gave me an identical render as Gc 2.2 in PP.  I don't have comparison images saved yet.  Maybe over the weekend.

BTW, what is the setting of your Tone Mapping?  Mine was HSV.