Mark leases an earth mover from SIMCO for $24,995 to be repaid by monthly instalments over 24 months. The conditions of the lease provide that if payments of the monthly instalments are not made on time, SIMCO can immediately take possession of the vehicle and all moneys owing for the duration of the contract will become immediately payable. There is no provision for a rebate or discounts should the outstanding balance become immediately payable if Mark defaults. Mark punctually pays the monthly instalments for the first six months, but then defaults in the seventh month. SIMCO takes possession of the vehicle and brings an action against Mark to claim the difference between the total rent payable over 24 months less the amount that Mark has paid over the past six months. Advise Mark.