A copy of the decision shall be mailed by the board within ten (10) days of the date of decision to the applicant, or if represented, then to his attorney, without separate charge. A copy of the decision shall also be mailed to all persons who have requested it and paid the prescribed fee. A copy of the decision shall be filed in the office of the board, which shall make a copy of such filed decision available to any interested party upon payment of the prescribed fee.