The THD(F) is wider bandwidth than the 1khz dashboard, so higher order harmonics and noise are contributing to the number.
20bit linearity may matter if the DAC has low noise floor as harmonics tend to disappear at lower levels. I don't see the dynamic range test for this DAC, so hard to say here.
20bit linearity may matter if the DAC has low noise floor as harmonics tend to disappear at lower levels. I don't see the dynamic range test for this DAC, so hard to say here.