It seems ExpertRAW is just putting a JPG file into an DNG container.  

I am comparing the dng files from ExpertRAW and the regular standard photo app. Samples are taken with the exact same settings.  

ExpertRAW Dngs have: 
- zero highlight recovery, reducing exposure and highlight settings makes it dull (that's how a jpg would behave, not a raw file)
- zero shadow recovery potential (unlike a real raw file)
- heavy JPG like artifacts and color tear-offs in dark areas of the image without any editing but maybe raising the shadows a little (not possible in real RAW)
- over sharpened details (sharpening should be done in raw processing not before), but this has become the least of the problems now

Those are very fundamental functions of a RAW file to adjust shadows and highlights. And it does work fine with the DNGs created with the regular app with the same exposure settings. Samples compare stock DNG vs Expert"DNG".

Stock App DNG left / Expert "DNG" right: Exposure and Highlights brought down a little, real DNG begins to show more details, fake DNG just gets dull like a jpg would, on neutral settings both looked similar

Expert "DNG" left / Stock App DNG right : minimal raise in the shadows showing jpg like soft compression artifacts in the fake DNG in dark areas 

Stock App DNG left / Expert "DNG" right: same photo as a whole with noticeable detail loss

right-side over sharpening of ExpertRAW (1:1)

Expert "DNG" left / Stock App DNG right: color tear-offs like a jpg, no detail in shadows