Issys_modifiable - deferred

Hi -

As per Oracle document if the parameter value in ISSYS_MODIFIABLE column ( in v$parameter view ) is ...

*IMMEDIATE - Parameter can be changed with ALTER SYSTEM regardless of the type of parameter file used to start the instance. The change takes effect immediately.
*DEFERRED - Parameter can be changed with ALTER SYSTEM regardless of the type of parameter file used to start the instance. The change takes effect in subsequent sessions.
*FALSE - Parameter cannot be changed with ALTER SYSTEM unless a server parameter file was used to start the instance. The change takes effect in subsequent instances.

ISSYS_MODIFIABLE value for audit_file_dest parameter is DEFERRED. I set the new value for this parameter but it is not showing in subsequent sessions. It accepted scope=spfile only and the change affected only after bouncing the database.

Can some one clarify me that ISSYS_MODIFIABLE = DEFERRED parameters are static or dynamic?

Thanks,