there is no way to know that, because there are no 3rd party measurements for a20h unfortunately. However I can confidently say that, setting subjective opinions aside, most balanced dacs have better sinad performances through their balanced outputs so, even if they are the same, performance of...
Oh about the noise floor, I tested it with a sensitive iem. low gain was similar to sp400 but high gain was much more noisier. No suprises there though, sp400's gain settings are so close that virtually you don't need to change them ever.