Is it obligatory to be fair between wives when one of them stipulates unequal treatment?

A woman's waiver of her right to equal division (of nights/time with her husband) differs in ruling depending on the time of the waiver:

- If the waiver is stipulated in the contract: The Hanbalis and Shafi'is hold that the marriage is valid, but the condition is void. As for the Malikis, they consider the condition void and permit the annulment of the marriage based on it before consummation. After consummation, the marriage becomes valid, and the condition is nullified.

- If the waiver is made after the contract with the wife's consent: This is permissible, and she has the right to retract her waiver whenever she wishes, based on the Almighty's saying: "And if a woman fears from her husband desertion or evasion, there is no sin upon them if they make terms of settlement between them - and settlement is best."