(2) for good cause shown, exceptions to the criteria stated herein or effectuated by operational bulletin, regarding the extent of the rehabilitation work required to be effectuated building-wide or as to individual housing accommodations, may be granted where the owner demonstrates that a particular component of the building or system has recently been installed or upgraded, or is structurally sound and does not require replacement, or that the preservation of a particular component is desirable or required by law due to its aesthetic or historic merit;
(3) the rehabilitation must have been commenced in a building that was in a substandard or seriously deteriorated condition. The extent to which the building was vacant of residential tenants when the rehabilitation was commenced shall constitute evidence of whether the building was in fact in such condition. Where the rehabilitation was commenced in a building in which at least 80 percent of the housing accommodations were vacant of residential tenants, there shall be a presumption that the building was substandard or seriously deteriorated at that time. Space converted from nonresidential use to residential use shall not be required to have been in substandard or seriously deteriorated condition for there to be a finding that the building has been substantially rehabilitated;
(4) except in the case of extenuating circumstances, the DHCR will not find the building to have been in a substandard or seriously deteriorated condition where it can be established that the owner has attempted to secure a vacancy by an act of arson resulting in criminal conviction of the owner or the owner's agent, or the DHCR has made a finding of harassment, as defined pursuant to any applicable rent regulatory law, code or regulation;