(a) Where deconversion occurs four years or more after the effective date of the conversion plan, the initial regulated rent shall be as agreed upon by the parties and reserved in a vacancy lease.
(b) Where deconversion occurs within four years after the effective date of the conversion plan, the initial regulated rent shall be the most recent legal regulated rent for the housing accommodation increased by all lawful adjustments that would have been permitted had the housing accommodation been continuously subject to the RSL and this Code.
(c)
(1) Where the rent, as agreed upon by the parties and paid by the tenant equals or exceeds the applicable amount qualifying for deregulation pursuant to subdivision (r) of this section, such accommodation and the rent therefor shall not revert to regulation under this Code.
(2) Initial regulated rents established pursuant to clause (a) of this subparagraph shall not be subject to challenge under section 2526.1(a)(2)(ii) of this Title.
(d)
(1) Within 30 days after deconversion, the new owner taking title upon deconversion shall offer a vacancy lease, at an initial regulated rent established pursuant to this subparagraph, to the holder of shares formerly allocated to the housing accommodation in the case of cooperative ownership, or the former unit owner in the case of condominium ownership. Such shareholder or former unit owner shall have 30 days to accept such offer by entering into the vacancy lease. Failure to enter into such lease shall be deemed to constitute a surrender of all rights to the housing accommodation.
(2) This clause shall not apply where deconversion was caused, in whole or in part, by a violation of any material term of the proprietary lease by the shareholder or former unit owner.