Upon the completion of an audit, the independent auditor shall file certified copies of the audit report with (1) the appointing authority, (2) in the case of a town, city or borough, with the clerk of such town, city or borough, (3) in the case of a regional school district, with the clerks of the towns, cities or boroughs in which such regional school district is located and with the board of education, (4) in the case of an audited agency, with the clerks of the towns, cities or boroughs in which such audited agency is located, and (5) in each case, with the Secretary of the Office of Policy and Management. Such copies shall be filed within six months from the end of the fiscal year of the municipality, regional school district or audited agency, but the secretary may grant an extension of not more than thirty days, provided the auditor making the audit and the chief executive officer of the municipality, regional school district or audited agency shall jointly submit a request in writing to the secretary stating the reasons for such extension at least thirty days prior to the end of such six-month period. If the reason for the extension relates to deficiencies in the accounting system of the municipality, regional school district or audited agency the request must be accompanied by a corrective action plan. The secretary may, after a hearing with the auditor and officials of the municipality, regional school district or audited agency, grant an additional extension if conditions warrant. Said auditor shall preserve all of his working papers employed in the preparation of any such audit until the expiration of three years from the date of filing a certified copy of the audit with the secretary and such working papers shall be available, upon written request and upon reasonable notice from the secretary, during such time for inspection by the secretary or his authorized representative, at the office or place of business of the auditor, during usual business hours. Any municipality, regional school district, audited agency or auditor who fails to have the audit report filed on its behalf within six months from the end of the fiscal year or within the time granted by the secretary shall be referred by the secretary to the Municipal Finance Advisory Commission established pursuant to § 7-394b, assessed a civil penalty of not less than one thousand dollars but not more than ten thousand dollars or both, except that the secretary may waive such penalties if, in the secretary’s opinion, there appears to be reasonable cause for not having completed or provided the required audit report, provided an official of the municipality, regional school district or audited agency or the auditor submits a written request for such waiver.