A teacher, being a member of The Manitoba Teachers' Society Executive Committee or of the Executive Committee of any branch thereof, or of any special committee of the Society, or being appointed an official representative or delegate of the Society, or any branch thereof, and being authorized by the Executive Committee of the Society to attend a meeting of the committee which he/she is a member of or to act as a representative or delegate, shall be excused from school duties for either purpose or both purposes. In any one school year the aggregate number of leave days approved division wide shall not exceed 30 days. In those years that a teacher is elected to the MTS Provincial Executive the aggregate number shall not exceed 35 days.