(a) A landlord may file an application for an adjustment of maximum rents on the ground that he owns a building containing no more than 19 housing accommodations (whether or not subject to control) and has incurred unavoidable increases in property taxes, fuel, utilities, insurance, and repairs and maintenance, excluding mortgage interest and amortization, and excluding allowances for depreciation, obsolescence and reserves, which have occurred since the Federal date determining the maximum rent. If, as determined by the administrator, the landlord has not been fully compensated by increases in rental income sufficient to offset such increases in operating costs, the administrator shall grant an adjustment of the maximum rents.

(b) Where the administrator finds, in considering the application under this section, that a present tenant is paying a rent less than the maximum rent, the administrator, upon request of the landlord, may reduce the maximum rent of the housing accommodation to the amount actually being paid, or to the highest maximum rent for comparable controlled housing accommodations in the structure, whichever is higher.

(c) A further application may not be filed under this section sooner than one year from the date of filing of the last prior application for an increase with respect to such property under this section, where such prior application resulted in the granting of an increase.