Just a quick reminder, prompted by me running into this issue face-first today. If you have an "older" drawing that has a previous version of a Property Set Definition using the same name as your current version, but that may be missing a property or two [or may use a now changed name for the property] that is used for a column in a Schedule Table Style, when you add the current Schedule Table Style to the file, it will not import the current version of the Property Set Definition, as it already exists in the drawing. All columns that reference properties that are missing, or going by an old name, will magically disappear from the Schedule Table Style.
Use Style Manager to manually update the old Property Set Definitions first, then bring in the Schedule Table Style, to avoid column loss. Those using ADT 2006 could make use of the new Standards features to update older drawings that are made part of a project.