Thanks for your quick reply!
WAVE_FORMAT_EXTENSIBLE is actually a Microsoft file type, unveiled back in the days of Win98, but commonplace on Win2000/XP ... It's a container for multichannel audio files, but the flag/header can be applied to 2-channel stereo .wav files as well ...
For info/links on "waveformatex" (same thing) and another type I use (b-format), see here:
http://people.bath.ac.uk/masrwd/wave_ex.html
I work with stereo AND multichannel audio, and I regularly deal with higher resolution sources (stereo and multichannel) that were recorded at 24/32-bits and 48/88.2/96kHz sample rates ... I would not want to reduce the sample rate of the original audio before attempting further processing (such as with Vogone) because I would be losing valuable data in the process! So, I'm more interested about the ability of Vogone to support higher sample rates than I am concerned about the 'waveformatex' file type.