(a) Where the maximum rent or any fact necessary to the determination of the maximum rent, or the dwelling space, essential services, furniture, furnishings or equipment required to be furnished with the accommodation, is in dispute between the landlord and tenant, or is in doubt, or is not known, or is required by section 2201.1(d) or (e) of this Title to be fixed or established, the administrator at any time, upon written request of either party or on his own initiative, may issue an order determining the facts, including the amount of the maximum rent, the dwelling space, essential services, furniture, furnishings and equipment required to be furnished with the accommodations. Where the administrator determines that the accommodations are subject to control, he shall also fix or establish the maximum rent therefor, together with the dwelling space, essential services, furniture, furnishings and equipment required to be furnished with the accommodations, unless such maximum rent had been previously fixed or established by the State Rent Commission or by the administrator.

(b) Where:

he may issue an order fixing or establishing the maximum rent, having regard for the maximum rents for comparable housing accommodations or any other factors bearing on the equities involved, consistent with the purpose of the Rent Law, including but not limited to the factor that such housing accommodations were created from housing accommodations which were vacated, on or after November 22, 1963, other than by voluntary surrender of possession or in the manner provided by Part 2204 of this Title. Where the housing accommodations were created from such accommodations, the administrator may give due consideration to the limitation on the amount of the rent adjustment which may be ordered, pursuant to the provisions of section 2202.3(a)(1) of this Part, in considering the equities involved. Such order shall fix or establish the maximum rent as of May 1, 1950, or the date of first renting, whichever is later, and may contain a directive that all rent collected in excess of the maximum rent fixed or established under this subdivision during the period beginning no earlier than two years prior to the date of the filing of the tenant's statement of violations, if any, or the date of the commencement of the proceeding to fix or establish the maximum rent, whichever date is earlier, shall be refunded to the tenant, together with six percent interest from the date of each such excessive payment of rent, within 30 days after such order shall become final.

(c) Where the landlord has failed to file an application or report required by the State Rent Commission or by either secton 2202.21(a) or (c) of this Part or section 35(a) or (c) of the New York City Rent and Eviction Regulations, the administrator at any time, upon written request of the tenant or on his own initiative, may issue an order establishing the maximum rent by decreasing the previous maximum rent for the housing accommodation by that amount which the administrator finds to be the reduction in rental value of the housing accommodation because of the decrease in dwelling space, essential services, furniture, furnishings or equipment. The administrator may take into consideration all factors bearing on the equities involved, consistent with the purposes of the Rent Law. Such order shall establish the maximum rent as of the date of such decrease of dwelling space, essential services, furniture, furnishings or equipment, and may contain a directive that all rent collected in excess of the maximum rent fixed or established under this subdivision, during the period beginning no earlier than two years prior to the date of the filing of the tenant's statement of violations, if any, or the date of the commencement of the proceeding to fix or establish the maximum rent, whichever date is earlier, shall be refunded to the tenant, together with six percent interest from the date of each such excessive payment of rent, within 30 days after such order shall become final.