(a)
(1) Compensation shall be computed on the average weekly wage earned by the employee under the contract of hire in force at the time of the accident and in no case shall be computed on less than a full-time workweek in the employment.
(2) Where the injured employee was working on a piece basis, the average weekly wage shall be determined by dividing the earnings of the employee by the number of hours required to earn the wages during the period not to exceed fifty-two (52) weeks preceding the week in which the accident occurred and by multiplying this hourly wage by the number of hours in a full-time workweek in the employment.
(b) Overtime earnings are to be added to the regular weekly wages and shall be computed by dividing the overtime earnings by the number of weeks worked by the employee in the same employment under the contract of hire in force at the time of the accident, not to exceed a period of fifty-two (52) weeks preceding the accident.
(c) If, because of exceptional circumstances, the average weekly wage cannot be fairly and justly determined by the above formulas, the commission may determine the average weekly wage by a method that is just and fair to all parties concerned.