it seems the 32k and 96-bit modes have different output behaviours.
while the short mode uses samples (much like DMC),
the long mode uses duties, of +vol and -vol levels...
interesting is the volume level:
short = 3/8
long = vol >> oversamples

of course this might be wrong, but that's what works pretty good...
the games? gradius2 (gofer's bgm) and rockman6 (intro bgm)

I wasted more than 30 hours trying a perfect noise output... and this has fixed the channel somewhat...