Ḥaḍrat Mawlānā Muftī Rashīd Aḥmad Ludhyānwī once asked his associates a question. He said “I perform four rakaʿāt sunnah mu’akkadah (emphasized) before ẓuhr in approximately nine minutes and the four rakaʿāt ghayr mu’akkadah (less-emphasized) before ʿaṣr and ʿishā in ten minutes. What is the reason for this?”
They remained silent.
He then answered, “The four rakaʿāt prior the ẓuhr is mu’akkadah (emphasized), hence there is no durūd or duʿā after the tashahhud in the first sitting, nor is there thanā in the third rakaʿāt. On the other hand, the four rakaʿāt before ʿaṣr and ʿishā ghayr mu’akkadah (less-emphasized), hence durūd, and duʿā is recited in the first sitting. Likewise, thanā is recited in the third rakaʿāt before sūrat-ul-fātiḥah, resulting in extra time being required.
(Anwār-ur-Rashīd, Volume: 3 Page: 94)
In another gathering he mentioned:
“The widespread practice of performing four rakaʿāt of nafl ṣalāh where one sits in the sitting of the second rakaʿāt until وَأَشْهَدُ أَنَّ مُحَمَّدًا عَبْدُهُ وَرَسُولُهُ and thereafter stands up to initiate the third rakaʿāt, is less virtuous; although ṣalāh will be deemed correct, the reward will be less. The sunnah and preferred method is to recite durūd, make duʿā and recite thanā when standing up for the third rakaʿāt”
(Jawāhir-ur-Rashīd, Volume: 11 Page: 19)
(Adapted from Itḥāf-ut-Ṭalabah, Page: 355/356 by Ḥaḍrat Mawlānā Muftī ʿUmar Farūq Luharvī)