(a) The MIR date shall be determined in accordance with subdivision (c) of this section whenever the Comptroller in the course of his audit determines that there is reasonable cause to believe that, as a substantive matter, payment may not properly be due to the contractor, in whole or in part.

(b) Whenever the Comptroller makes the determination set forth in subdivision (a) of this section, he shall send the contractor written notice of such determination, unless he suspects illegal or similar activity on the part of the contractor which would make such notice inappropriate, in which event he shall make a dated written record of such determination in his files. The written notice shall include a request for all information and material which the Comptroller deems necessary to determine whether or not payment is properly due, and a copy of such notice shall be sent to the agency. Promptly upon completion of his audit, the Comptroller shall notify the contractor and agency of the results of his audit unless he suspects illegal activity, in which event he shall make a dated written record of his audit conclusions for his file.

Where, after an audit pursuant to subdivision (a) of this section, the Comptroller determines that all or a portion of the amount claimed by the contractor is, in fact, due, the MIR date of the invoice shall be the original MIR date increased by a number of days equal to the number of days from the date that the Comptroller sends the contractor the written notice required by subdivision (b) of this section, or in the case of suspected fraud, from the date the Comptroller enters the written determination required by subdivision (b) in his files, to the date that the Comptroller sends written notice to the contractor of the resolution of the matter.