|(a) The inspector general may waive the calculation of an overpayment by extrapolation, as described in §371.214(r)(2) of this subchapter (relating to Resource Utilization Group Classification System), to any or all of the Resource Utilization Group (RUG) classifications found in error. (b) A provider must request a waiver of extrapolation in writing on or before the 15th calendar day after receipt of the final notice of overpayment. The provider's request for waiver of extrapolation must include sufficient evidence to demonstrate good cause for the waiver. The Office of the Inspector General may request additional evidence or documentation from the provider or other informational sources in evaluating the request. (c) The inspector general is vested with the sole discretion to evaluate the provider's showing of good cause and to determine whether waiver of extrapolation is warranted. (d) The decision to grant, deny, or modify a request for waiver of extrapolation is not subject to administrative or judicial review.