Trigger r.ExposureOffset in DefaultScalability.ini settings?

I’m setting up a low scalability target for VR in BaseScalability.ini.

I’d like to completely disable r.EyeAdaptationQuality (due to perf cost) by setting it =0 for lowest setting and compensate with an r.ExposureOffset=2. Without this offset, the scene is a bit too dark.

When I define these lines in BaseScalability.ini, r.ExposureOffset does not appear to function at all (attempted various “spin the knob” values to 5, 0, etc).

Is there a way to ensure the command “r.ExpsureOffset” fires based upon scalability settings?