you are trying to build an "OS9 audiophile" setup by playing 16 bit files from OSX and trust a free japanese measuring tool more than math or the coreaudio docs. that already overwhelms me.
coreaudio can transport 16 bits as is, too - as far as i know - but that some app shows active bits of a stream which doesnt exist is only a phenomen of that specific setup.
and if you think that the conversion of 16 bits to 32 and back to 16 involves loss of precision for some reasons not explainable with maths, then use a CD player. but one without digital volume control.
