Currently, using the Membership module on the db side, if you want to create a new category that will be considered the same level as a previous category, but want to retain the old category name, you cannot renew a Membership using the new name and have the system consider it the same level - RE requires it to be an upgrade or downgrade. So, in order for the system to count our renewals as the same level using the new name, we have to replace the old name with the new name, and wipe out any history of that levels original name. The upgrade, downgrade, same buttons need to operate separate from the category.
I forgot to mention my one suggestion regarding this issue. Once a category is made inactive, the system doesn't consider it when future renewals are made to the new category that is considered the same level. We attempted that and it doesn't work. Also, we thought we could import the new category and enter Same for the renewal direction, and because we were importing, it would override the system rule--and BB support also said that would work. Unfortunately, the directional radio buttons for upgrade, downgrade and same are not offered as fields to be used in an import.