ALTER SYSTEM SET job_queue_processes=20 SCOPE=SPFILE

SQL> ALTER SYSTEM SET job_queue_processes=20 SCOPE=SPFILE;
System altered.

SQL> show parameter job_queue_processes

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
job_queue_processes                  integer     1000

even after I bounce the instance the job_queue_processes remains at 1000.

Any ideas?