(vi) for the purpose of determining if the owner establishes by a preponderance of the evidence that the overcharge was not willful, examination of the rental history of the housing accommodation prior to the four-year period preceding the filing of a complaint pursuant to this section shall not be precluded;
(vii) for the purpose of determining any adjustment in the legal regulated rent pursuant to section 2522.8(a)(2)(ii) of this Title, or any adjustment pursuant to a guideline promulgated by the New York City Rent Guidelines Board that requires information regarding the length of occupancy by a present or prior tenant or the rent of such tenants, review of the rental history of the housing accommodation prior to the four-year period preceding the filing of a complaint pursuant to this section shall not be precluded;
(viii) for the purposes of establishing the existence or terms and conditions of a preferential rent under section 2521.2(c) of this Title, review of the rental history of the housing accommodation prior to the four-year period preceding the filing of a complaint pursuant to this section shall not be precluded;
(ix) for the purpose of establishing the legal regulated rent pursuant to section 2526.1(a)(3)(iii) of this Title where the apartment was vacant or temporarily exempt on the base date, review of the rental history of the housing accommodation prior to the four-year period preceding the filing of a complaint pursuant to this section shall not be precluded.
(3)
(i) The legal regulated rent for purposes of determining an overcharge shall be deemed to be the rent charged on the base date, plus in each case any subsequent lawful increases and adjustments.