Is it permissible to change the rental value in a finance lease contract based on the lending rate from the Central Bank, taking into consideration that "the rental value may change according to the lending rate from the Central Bank"?

Financial leasing (Ijara Tameeliya) is permissible if its conditions and regulations are met. It is also permissible for the rent to be variable, dependent on a controlled index that does not lead to dispute, in two ways: First, explicitly defining the rent for each year. Second, linking the rent to a controlled index known to both parties, such as "the interest rate at the Central Bank" or "the interest rate in the London market," provided that the amount of the rent is known at the beginning of each period. This has been affirmed by juristic councils and institutions, based on the principle that excusable ignorance does not lead to dispute, and that the determination eventually leads to knowledge.