I believe you are referring to lossy formats, as re-encoding one lossless format to another will not degrade quality. Re-encoding the lossless format to 320kbit

I believe you are referring to lossy formats, as re-encoding one lossless format to another will not degrade quality. Re-encoding the lossless format to 320kbit Vorbis is what he's requesting which will ensure minimum quality degradation while still reducing the file size.