The rent to tenants at the time of filing the application for conversion shall not be increased for the period between the filing of the application until relocation takes place or until the subdivision is denied or withdrawn, except that such period shall not exceed two years. At the end of such period, and for one-year period thereafter, any increase in rent shall not exceed the proportionate increase in the residential rent component of the “Bay Area Cost of Living Index, U.S. Dept. of Labor,” over that period of time, provided, that the rental increase provisions of this section shall be operative only in the absence of other rent increase or arbitration laws. In cases of hardship due to unusual circumstances to the subdivider, or in cases where a rent increase authorized herein is considered by the tenant to be not consistent with increases in the residential rent component of the “Bay Area Cost of Living Index, U.S. Dept. of Labor,” either a subdivider or a tenant may request relief under this Section from the Director of Public Works or his or her designee. In considering the reasonableness of a rent increase, the Director shall consider the current rent paid for comparable units in comparable areas.