Posted.
Well. I turned over a rock and found a bee's nest to cross metaphors.
OS-X has its own version of AIFF and true to their heritage, Apple carefully hid all the clues to what they did. They're right up front about the inability of older software to open OS-X generated AIFF files which are really AIFFC files with the compression turned off, the header flagged (and hidden), and the byte order reversed.
Are you following this? I'm not either. I need to go back and read the explanation again. I still have no mention of what a "Packed 24-bit" file is.
I did get a Hex Editor called Hex Fiend to run and I'm able to go down through the file headers and at least see what the header thinks is going on.
See, so right away there's a problem because my "PC" sound file uses Big Endian byte structure and PCs use Little Endian.
Who knew?
Koz