(14) In the case of an improvement constituting a moderate rehabilitation as defined in section 5-02 of title 28 of the Rules of the City of New York, an owner may elect that the total cost for such improvement be deemed to be the amount certified by the Office of Tax Incentive Programs of HPD in the certificate of eligibility and reasonable cost issued by such office with respect to such improvement. Such election shall be binding on the DHCR and shall waive any claim for a rent increase by reason of any difference between the total cash paid by the owner and such lesser certified amount.
(15) Where during the processing of a rent increase application filed pursuant to paragraph (2) of this subdivision, tenants interpose answers complaining of defective operation of the major capital improvement, the complaint may be resolved in the following manner:
(i) Where municipal sign-offs (other than building permits) are required for the approval of the installation, and the tenants' complaints relate to the subject matter of the sign-off, the complaints may be resolved on the basis of the sign-off, and the tenants referred to the approving governmental agency for whatever action such agency may deem appropriate.