In any case, I am 99% sure it only deals with 16 bits, but I haven't queried the PS Audio folks yet to get the real answer.
Ahh...does this mean the 96 and 192 kHz up-sampling modes are actually 16/96; 16/192? That doesn't seem right?? I guess it won't really matter come December!! Ironically, the 24/96 files that I feed the Duet-DLIII do sound superior to the majority of my Red Book files (just think what they'll sound like via the PWD).