When is the prostration for forgetfulness performed before the closing salam and when after the closing salam

Question : May Allah reward you with good. The prostration for forgetfulness is performed after the prayer when it is due to an added element, and before the closing salam when it is due to omitting an obligatory act. Before the closing salam for an obligatory act, and after the closing salam for an added element.

Answer : No, that is an addition. If it is an addition, it is after the closing salam. If it is the omission of an obligatory act, it is before the closing salam.