(2) costs shall only be recoverable by a landlord pursuant to this subparagraph for an individual apartment improvement if (i) the apartment was timely registered as vacant by no later than the thirty-first of December in each of two thousand twenty-two, two thousand twenty-three, and two-thousand twenty-four, provided that a landlord may recover costs on this basis no more than once, or (ii) if the apartment is vacant following a period of continuous occupancy of at least twenty-five years that occurred immediately prior to the commencement of such individual apartment improvement;
(3) costs shall only be recoverable by a landlord pursuant to this subparagraph if such landlord has received prior certification to recover costs pursuant to this subparagraph from the division of housing and community renewal based on establishing that the landlord satisfies one of the eligibility criteria delineated in clause two of this subparagraph, provided further that such certification shall not be deemed as evidence that the work performed or costs claimed for the individual apartment improvement was substantiated or to otherwise act as a defense in any subsequent rent overcharge proceeding, determination, or audit;
(4) increases to the legal regulated rent pursuant to this subparagraph shall be permanent;