Data CD vs Audio CD

I was recently engaged in a conversation with an audiophile who claimed that he could hear the difference between audio tracks recorded on CDs specifically designated for Audio and those designated for Data.Putting aside the fact that hearing accuity declines with age (this guy is 50) and that I have a reasonable amount of respect for him technically, my point is as follows. A digital copy is bit for bit perfect (i.e. identical) yet his argument seems to suggest that audio CDs are of a higher quality and therefore less prone to errors. If this is the case then surely the data CDs should be of higher quality, as the integrity of audio data is less critical that of data. Does anyone have an explanation to back his claims?