It is quite possible that the index space is including your clustered indexes.
Try running the scripts shown in this article:
http://jasonbrimhall.info/2010/05/19/tablespace-update/
Jason...AKA CirqueDeSQLeil
_______________________________________________
I have given a name to my pain...MCM SQL Server, MVP
SQL RNNR
Posting Performance Based Questions - Gail Shaw[/url]
Learn Extended Events