Yes but recorded sound is not live. Therefore you roll tubes to find the sound you think sounds live. The equipment manufacturer may have used a tube that you think sounds live in which case no need. In general Ihave found that I get the most pleasing sound if I roll tubes. On occasion I don't, but it's the exception not the rule.
Does tube rolling with regard to CDP mean...
Bringing more color into the sound reproduction? If that is the case then tube rolling would be: changing tubes until you find the right coloration. But isn't it true that the live sound is what we are after? In that case tube rolling should mean: changing of tubes until the sound resembles live music.
Chris
Chris