a) A teacher, being a member of The Manitoba Teachers' Society Executive Committee, or of a committee of the Society, or being appointed an official representative or delegate of the Society to attend a meeting of the committee of which he/she is a member, or to act as a representative of a delegate of the Society in a matter of Society business requiring absence from school, shall have the right to attend such meetings or to act as representative or delegate, and shall be excused from school duties for either purposes or both purposes for not more than a total of five (5) teaching days in any school year, provided that a substitute satisfactory to the Division can be secured, and that the cost of providing a substitute is assumed by the Society and shall not be a charge upon the Division. The maximum total leave for executive duties shall not exceed ninety (90) days in any school year. Additional leave of absence up to eight (8) days in the school year shall be granted to each of the four (4) members of the Negotiating Committee of the Association and an additional leave of absence up to fifty (50) days in the school year shall be granted to the President of the Association. Any days in addition to the above shall be subject to the approval of the Chief Superintendent.