Is it obligatory to fully extend all Madd Munfasil in the recitation of Hafs, or is it permissible to extend some and not others?

Most narrations from Hafs involve extending Al-Munfasil (the separated madd) throughout the entire Qur’an. Al-Dani, in "Al-Tayseer," and Al-Shatibi, in "Hirz Al-Amani," restricted themselves to his madd. Ibn Al-Jazari and Al-Dabba' mentioned that Al-Hammami narrated the shortening of Al-Munfasil from Hafs. Accordingly, extending Al-Munfasil is obligatory for Hafs according to those who recite from him via the path of Al-Shatibiyyah and Al-Tayseer, but it is not obligatory according to those who recite from him via the path of Al-Tayyibah and Al-Nashr. Mixing and combining recitation paths is forbidden, disliked, or blameworthy. One must beware of combining paths and distinguish them from each other; otherwise, one will fall into what is impermissible. Among the best books that clarify the various paths narrated from Hafs is "Sarih Al-Nass fi Al-Kalimat Al-Mukhtalif Fiha 'an Hafs" by Al-Dabba'.