All the styles for an AEC and AECB type drawing are located in the Named Object Dictionary of a drawing database. You can find all of the property sets under the AEC_PROPERTY_SETS_DEFS. In this dictionary there is a list of all of the property sets in a drawing. I am not familiar with LISP but I believe you are using another method to get this list. They same list can be found for Schedules under the AEC_SCHEDULE_TABLE_STYLES Named Object Dictionary.
I thought i might add that if you download the AutodeskMGDDBG application from this link. It will allow you to "snoop" an object or a database and see all of the named object dictionaries in the drawing.
You can view this webpage to download the file instead of the direct link above if you prefer.