Is it permissible for the husband to take more than he gave his wife in dowry when the woman ransoms herself out of marriage (i.e. khulʿ)?

Imām Ibn al-Jawzī (d. 597/1201) summarized the scholars' opinions in his book "Zād al-Masīr" as follows:

1. It is permitted. [ʿUmar ibn al-Khaṭṭāb, ʿUthmān, ʿAlī, Ibn ʿAbbās, al-Ḥasan, Mujāhid, al-Nakhaʿī, al-Ḍaḥḥāk, Mālik, al-Shāfiʿī].
2. It is not permitted. [Saʿīd ibn al-Musayyib, ʿAṭāʾ, al-Shaʿbī, Ṭāwūs, Ibn Jubayr, al-Zuhrī, and Aḥmad ibn Ḥanbal. Also reported from ʿAlī and al-Ḥasan].