Inspiron 13 7373 Content Adaptive Brightness Control

I have the typical symptom with the screen/window dimming depending on how dark the overlay image is.  Only occurs in battery mode.  This becomes a big problem in viewing .pdf files with the grey borders.  

I have tried everything including messing with the registry edit as described in:

https://mikebattistablog.wordpress.com/2016/05/27/disable-intel-dpst-on-sp4/

Dell support now wants me to send the laptop in for repair which I assume will come back the same problem...or has anyone have success sending the laptop in for the same problem?  Thanks, Mike