The annual salary of elected officials of County Council shall be $30,000 for the president of Council and $27,500 for the other members of Council and may be changed by ordinance or upon a recommendation by the New Castle County Compensation Commission which has been adopted and ordained by County Council, except that no increase shall be effective for any such official whose term will expire within 6 months from the time enactment of such ordinance. Such officials shall receive their actual and necessary expenses incurred in the performance of their duties of office.