I have managed to get some purplish SSS in the ears by ramping up the R and B channels to around 20, leaving the G channel at zero. I think the values are too high because the texture there is blooming. Also, there is an overall softening of the rest of the model due to the higher values but this is the best I can do. No purple around the eyes from what I can observe.

There is a bug on the PhysicalSurface SSS as reported by Chromestar, I believe. If all the SSS channels are set to the same value, they negate each other and you get no Subsurface scattering. At the moment, I am just as stumped as you are. Maybe that's the way it should be but until a tech says otherwise we'll need to sit tight and figure out a workaround for your particular needs.