Can the Missed Tasbeehaat in Salaatut Tasbeeh be Compensated for by Sajdah Sahw?

Q: Salaah-488: If one realised that one recited fewer than 300 Tasbeehaat in the Salaatut Tasbeeh, can this be compensated for by Sajdah Sahw? lf not, how can they be made up?

Answer: If one realised this after completing the salaah, Sajdah Sahw will not be binding because Sajdah Sahw compensates for an omitted Waajib (compulsory) act and the Tasbeehaat are not Waajib. In such a case, the salaah will be regarded as Nafl salaah and the rewards of Salaatut Tasbeeh will be lost. And Allaah knows best what is most correct.

Fatawa Rahimiyyah vol.2