Server Administration :: Command To Determine Which Table Can Benefit From Shrinking

I use following command to determine which table can benefit from shrinking

select * from
table(dbms_space.asa_recommendations('FALSE', 'FALSE', 'FALSE'))
order by reclaimable_space desc

then i give following command to get reclaimable space

alter table t1 enable row movement ;
alter table t1 shrink space cascade;
alter table t1 disable row movement ;

in table t1 427MB was shown as reclaimable space, after executing above commands, i run dbms_space procedure again to check the out come, but result was same.I understand tablespaces are by default ASSM in 11g, none of table has LONG datatype or LOB indexes or MVIEW with ON COMMIT.