Is the second wife entitled to demand a retroactive division for the days she spent with the first wife, or does equitable division begin from the moment she demands equality?

A wife who agrees to waive some of her right to a fair division of time (qasm) may retract that waiver and demand that her husband deal justly in dividing his time between her and his other wife, whether this occurs after the marriage contract or was a condition within the contract itself.

However, she does not have the right to demand compensation for the past time divisions she relinquished, as it is considered akin to something that has been received. She only has the right to demand a just division of time between her and the other wife from the moment she makes that demand.