@KenC
I committed to pixelshift branch
To see the raw values you have to select Demosaic method ‘none’ and preferably also disable all preprocessing steps like auto ca-correction and so on.
Then the navigator shows the raw value after black level subtraction in the range of the original raw data.
You have to select the [0-255] range in navigator to get the raw values in full range 
Edit: I added another commit because I forgot to round instead of truncate.