alter table shrink space does not work for me 10.2

This is my first post, apologize if this is the wrong place, and let me know where should I go for this.

This is Oracle 10.2 AIX.

I have a table CXADMIN.DAILY_INVENTORY has 1.5 million rows with 169 bytes each row.  The real data size is around 260 MB but the table itself is now 25 GB.  It has 52k extents. 

I tried to do an alter table cxadmin.daily_inventory shrink space cascade; and it did not change the size of the table.  When I export and import the table to the other database it only takes 260 MB.  I am sure if I do create table as select, then truncate the table then insert it back, it will shrink the space.  But what is bothering me is that "alter table shrink space " does not work on this one.