An officer or enlisted member of the national guard detailed to serve on any board or commission ordered by the governor, or under the governor’s authority by the commanding officer of the national guard, or on any court of inquiry or court-martial ordered by proper authority under any provision of this title, is entitled to receive pay and allowances at the highest rate provided for national guard members of the same grade in the national guard of the United States for each day that officer or enlisted member is actually employed on the board or court, or engaged in the business of the board or court, including any day the officer or enlisted     member is traveling to and from the board or court. The sum received may not exceed ten days’ pay and the actual traveling expenses and subsistence unless, upon application of the president of the court-martial or the presiding officer of the board, the officer appointing the court or board has authorized the court or board to sit for a longer period, or in case of a court-martial, the governor or officer ordering the court has authorized the court to sit for a period longer than ten days.