In order to prevent confusion our system was setup to keep all three the same. That way if only one is visible in a particular table, you will still be able to find what you're looking for. I have considered changing Common Name to map to the part parameter Description instead, but haven't actually implemented it yet. Doing so would allow simple searches to return objects based on description. Right now search by description we have to use advanced searches with that parameter added to the search. Also, I should mention that all three of the values CAN be changed after creation (including Number) as long as the user doing the changing has the necessary permissions.
Tom U.