Phonak Target Gain & MPO: gain versus target gain?

In the sample Gain & MPO graph, why are the light lines, “target gain”, mostly visible instead of being “hidden” underneath the heavy “gain” lines? If “target gain” represents the result of the fitting formula, what does “gain” represent?

Edit: the amount of variation between gain and target gain varies by program (calm situation, speech in noise, etc., etc.).


I am interested in this as well Brec😜

I guess no one knows the answer!