Praise be to Allah.
Ibn Qudaamah said: It is recommended that he not take from her more than he gave to her. If he does that, it is makrooh (disliked) but it is still valid. This was narrated from ‘Uthmaan, Ibn ‘Umar and Ibn ‘Abbaas, because Allaah says (interpretation of the meaning):
“then there is no sin on either of them if she gives back (the Mahr or a part of it) for her Al-Khul‘ (divorce)”
Al-Rabee’ bint Mu’awwidh said: I asked my husband for a divorce (khula’) for everything except my head cover, and ‘Uthman ibn ‘Affaan permitted me to do that. Such incidents become well known, (and as no one spoke against it), thus there is consensus on this matter. Since this is proven to be the case, then it is a permissible action, even though it is disliked (makrooh), because it was narrated in the hadeeth of Jameelah: “So he commanded him to take his garden back from her and no more than that.” And it was narrated from ‘Ataa’ (from Ibn ‘Abbaas) that the Prophet (peace and blessings of Allaah be upon him) regarded it as makrooh to take more from a wife divorced by khula’ than had been given to her. So we may reconcile the aayah and the hadeeth by saying that the aayah indicates that it is permissible to take more than was originally given, and the prohibition on taking more in the report indicates that doing this is makrooh.