(iv) a rental practice proscribed under section 2525.3(b), (c) and (d) of this Title has been committed, the rent shall be established at the lowest of the following amounts set forth in paragraph (3) of this subdivision.
(3) These amounts are:
(i) the lowest rent registered pursuant to section 2528.3 of this Title for a comparable apartment in the building in effect on the date the complaining tenant first occupied the apartment; or
(ii) the complaining tenant’s initial rent reduced by the percentage adjustment authorized by section 2522.8 of this Title; or
(iii) the last registered rent paid by the prior tenant (if within the four year period of review); or
(iv) if the documentation set forth in subparagraphs (i) through (iii) of this paragraph is not available or is inappropriate, an amount based on data compiled by the DHCR, using sampling methods determined by the DHCR, for regulated housing accommodations.
(4) However, in the absence of collusion or any relationship between an owner and any prior owner, where such owner purchases the housing accommodations upon a judicial sale, or such other sale effected in connection with, or to resolve, in whole or in part, a bankruptcy proceeding, mortgage foreclosure action or other judicial proceeding, and no records sufficient to establish the legal regulated rent were made available to such purchaser, such orders shall establish the legal regulated rent on the date of the inception of the complaining tenant's tenancy, or the date four years prior to the date of the filing of an overcharge complaint pursuant to section 2526.1 of this Title, whichever is most recent, based on either: