100.13. In disciplinary matters, the court of arbitration may confirm, amend or set aside the decision of the employer; it may, if such is the case, substitute therefor the decision it deems fair and reasonable, taking into account the circumstances concerning the matter.
However, where the collective agreement provides for a specific penalty for the fault alleged against the employee in the case submitted to arbitration, the court of arbitration shall only confirm or set aside the decision of the employer, or, if such is the case, amend it to make it conformable to the penalty provided for in the collective agreement.