On a case-by-case basis, the commissioner may provide for the application of emission standards for total fluorides less stringent than those otherwise required in section 209.2(d) of this Part if the owner or operator can demonstrate that exemplary operation and maintenance procedures were used with respect to the emission control system and that proper control equipment was in operation during the emission test. Such less stringent standards shall not exceed:
N.Y. Comp. Codes R. & Regs. Tit. 6 § 209.7