Is it obligatory or permissible to shorten supererogatory prayers by analogy with the two Rak'ahs of Fajr?

Supererogatory prayers (Nawafil) are divided into three categories:

1. Nawafil where brevity is sunnah (recommended): Such as the two rak'ahs before Fajr prayer (as Aisha, may Allah be pleased with her, said: "The Prophet, peace and blessings be upon him, would shorten the two rak'ahs before the Fajr prayer so much that I would say: Did he even recite Surah Al-Fatiha?!"). This also applies to Tahiyyat al-Masjid (greeting the mosque) if the Imam is delivering a sermon, starting the night prayer with two short rak'ahs, and the two rak'ahs after circumambulating the Kaaba (Tawaf).

2. Nawafil where prolongation is sunnah (recommended): Such as the eclipse prayer (due to the Prophet's action, peace and blessings be upon him, where he stood for a long time, equivalent to reciting Surah Al-Baqarah), and the night vigil (Qiyam al-Layl), which Aisha, may Allah be pleased with her, described as being long and beautiful when she said: "So do not ask about their beauty and their length."

3. Nawafil where neither brevity nor prolongation is mentioned: Scholars differ on whether it is better to prolong the standing (qiyam) or to increase the number of bowing (ruku') and prostrations (sujud). Hanbalis: Increasing bowing and prostrations is better, based on the Prophet's saying, peace and blessings be upon him: "The closest a servant is to his Lord is while he is prostrating." Shafi'is: Prolonging the standing is better. Some scholars: Differentiate between day and night; during the day, increasing bowing and prostrations is better, while at night, prolonging the standing is better.

In conclusion, for acts of worship where the Prophet, peace and blessings be upon him, specified either brevity or prolongation, the Sunnah is to follow his example. For all other cases, the choice between prolonged standing and increasing bowing and prostrations is left to what brings more benefit and humility to the worshiper's heart, based on the Prophet's saying, peace and blessings be upon him: "So if he prays alone, let him pray as he wishes."