(a) The services of the State Board of Mediation and Arbitration shall be available to municipal employers and employee organizations for purposes of mediation of grievances or impasses in contract or contract reopener negotiations and for purposes of arbitration of disputes over the interpretation or application of the terms of a written agreement and, if such service is requested by both the municipal employer and the employee organization except as provided in section 7-473c for purposes of arbitration of impasses in contract or contract reopener negotiations. Whenever any impasse in contract or contract reopener negotiations is submitted to arbitration, the decision of the arbitration panel or arbitrator shall be rendered no later than twenty days prior to the final date by which time the budget-appropriating authority of the municipality is required to adopt its budget or forty days after the close of the arbitration hearing, whichever is later, provided that in no case except when such arbitration service is requested or mandated after the final budget adoption date shall such decision be rendered later than five days prior to such final budget adoption date. Nothing contained herein shall prevent any agreement from being entered into in accordance with the provisions of subsection (e) of section 7-474 .
(b) Nothing in this section is intended to prevent the use of other arbitration tribunals in the resolution of disputes over the interpretation or application of the terms of written agreements between municipal employers and employee organizations.