How many bits are the raw DNG files produced by J2R? I am guessing 14bit...?
The EXIF says "Bits per sample 16 16 16" for the full resolution image, but that is simply TIFF specifications ... most RAW images (camera) contain 14bit but hold more information that a 16bit TIFF.
So you would need to ask the maker ...
I am told 16-bit