All applications and petitions submitted in writing and in a form prescribed by the Planning or Zoning Commission as the case may be, shall be considered at a public hearing to be held within time frames prescribed in the Connecticut General Statutes and decided upon by said Commission(s) within the time frames allowed in the Connecticut General Statutes. The petitioner may consent to extension of the periods provided for hearing and for adoption or denial or may withdraw such petition. The Commission(s) shall not be required to hear any petition or petitions which are substantially the same more than once in a period of 12 months.