Does the prostration of forgetfulness apply to supererogatory prayers, whether it is pre-emptive (Qabli) or post-emptive (Ba'di)?

The best practice regarding the prostration of forgetfulness (sujud al-sahw) is to act in accordance with the sayings and actions of the Prophet, peace and blessings be upon him. Thus, one should prostrate before the salutation (taslim) for what was specified to be done before it, and after it for what was specified to be done after it. For what was not specified to be done at either time, the worshiper has the choice, because of the Prophet’s saying, "If a man adds or subtracts, let him perform two prostrations." As for the prostration of forgetfulness in supererogatory (nafilah) prayers, it is required just as in obligatory (fard) prayers, according to the general consensus of scholars, due to the Prophet’s saying, "If one of you forgets, let him perform two prostrations," and "If one of you forgets and adds or subtracts, let him perform two prostrations." The Malikis, however, made an exception for five cases in which the prostration of forgetfulness in supererogatory prayers differs from that in obligatory prayers.