Reducing the Size of the Table or Index 
You may want to reduce the size of a table/index (or the size of all objects in a tablespace) during a reorganization or for an export/import if a relatively large amount of memory space is required and occupied (allocated), but is not used by the relevant objects.
Choose Reduce object size: yes, if you want SAPDBA to automatically try to reduce the size of the objects (allocated storage space) during the reorganization or for an export/import. To determine the actual storage space occupied, SAPDBA uses the ORACLE command ANALYZE TABLE <Name> ESTIMATE STATISTICS or ANALYZE INDEX <Name> VALIDATE STRUCTURE. Using these values and the current storage parameters, a new value is determined for the space to be allocated. If this value is smaller than the storage space allocated before the reorganization or export/import, the size of the object is reduced to this value.