With visio I did this about a year ago, so whatever version was current then or more recent would do.
I'm not sure why an extra config item type attribute was added when change has one already, but that's life I guess. Anyway from the way you have explained it, when your new attribute was created it still pointed to the same basic table of class types. I'd look through the list you have, compare that by eye with the contents of md_classtype. I still think that is the correct table so perhaps you need to look carefully at the relationship you added from the attribute to the table? Sorry I cannot be of further help and perhaps its time to call your local support team who could look at the database.