Many of JA’s measurements were confounded by the noise floor. In particular the resolution. If you read his follow on measurements of the next release of the software he notes that the system is linear at 24 bits. I.e. the resolution is at the limits of his measurements. The accuracy isn’t 24 bits, but no current audio DAC is 24 bit accurate.
The Mk II will measure better than the DS, in particular the noise floor will be lower. There will be less distortion. The output resolution can’t be greater than the input resolution for any DAC.