100.12. In the exercise of his duties the arbitrator may
(a) interpret and apply any Act or regulation to the extent necessary to settle a grievance;
(b) fix the terms and conditions of reimbursement of an overpayment by an employer to an employee;
(c) order the payment of interest at the legal rate, from the filing of the grievance, on any amount due under an award he has made.
There must be added to that amount an indemnity computed by applying to that amount, from the same date, a percentage equal to the amount by which the rate of interest fixed according to section 28 of the Act respecting the Ministère du Revenu (chapter M-31) exceeds the legal rate of interest;
(d) upon request of a party, fix the amount due under an award he has made;
(e) correct at any time a decision in which there is an error in writing or calculation or any other clerical error;
(f) in disciplinary matters, confirm, amend or set aside the decision of the employer and, if such is the case, substitute therefor the decision he deems fair and reasonable, taking into account the circumstances concerning the matter. However, where the collective agreement provides for a specific sanction for the fault alleged against the employee in the case submitted to arbitration, the arbitrator shall only confirm or set aside the decision of the employer, or, if such is the case, amend it to bring it into conformity with the sanction provided for in the collective agreement;
(g) render any other decision intended to protect the rights of the parties.