In supererogatory prayers other than the rawatib sunnah, after how many rak‘ahs is it more virtuous to give salām?

According to the Hanafis, in supererogatory prayers performed at night, it is more virtuous to give salām after every two rak‘ahs, and in those performed during the day, after every four rak‘ahs. It is considered disliked (makruh) to perform more than four rak‘ahs with a single salām in daytime prayers, and more than eight rak‘ahs with a single salām in night prayers. (Mevsılî, el-İhtiyâr, 1/67-68; Aliyyü’l-Kârî, Fathu bâbi’l-‘inâye, 1/394) According to the Shafi‘is, salām is given after every two rak‘ahs in supererogatory prayers, whether performed during the day or at night. (Māwardī, el-Hāwī, 2/289; Marghīnānī, al-Hidāyah, 1/67)

Source: T.C. Diyanet İşleri Başkanlığı, Din İşleri Yüksek Kurulu