Have you gone through a blind test? Because most musicians, DJs and producers I know that tried it, either couldn't tell a difference, or told it wrong, on a big enough sample. I'm not even mentioning people who are not music industry professionals.
Don't forget that the early encoders were pretty bad. It seems conceivable that a old encoders might have produced 320 kbit mp3s that were distinguishable from CDs in blind tests. Perhaps tempodox gave up on mp3s before they got good?
