All perfect praise be to Allah, The Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
As long as the landlord and the tenant agree on one of the two offers before leaving the contract session, then this is permissible, and there is no problem regarding the difference of the rent according to the length of the lease. Most scholars held that it is permissible for the Muslim to sell his commodity at a specified price on the spot or at a higher deferred price.
The Kuwaiti Encyclopedia of Fiqh reads, “If a person sells the commodity for one thousand as an immediate payment or for one thousand one hundred to be paid within a year ... if the two contracting parties agreed on one of the two specified prices before leaving the session of the contract, the sale is valid ... This is the view held by the majority of scholars.”
Allah knows best.