1. Parties who have submitted a dispute to a permanent arbitration court for resolution in accordance with its rules may in provisions accompanying the arbitration clause or by later agreement modify the provisions of the rules. … Acceptance by the permanent arbitration court (or its authorities) of changes to the rules made by the parties is another issue. The arbitration court may consent to conduct the proceeding in compliance with the rules as modified by the parties, or not accept the changes. However, if it does not accept the changes, the permanent arbitration court can only refuse to accept the case for consideration (Civil Procedure Code Art. 1168 §2), but it cannot conduct the proceeding according to the rules in the version that does not reflect the changes made by the parties if they refuse to give up those changes. If the permanent arbitration court has accepted the case for consideration, then it is required to respect the intent of the parties as manifest in the changes they have made to the rules of the arbitration court.
2. The priority of the intent of the parties over the rules of the permanent arbitration court applies as well when the parties have agreed that the arbitration proceeding is to include two instances, while the rules provide that the proceeding has one instance.
3. If the parties agree that the proceeding before the arbitration court is to include more than one instance (Civil Procedure Code Art. 1205 §2), then the arbitration regulations of the Civil Procedure Code and the principles and rules resulting therefrom also apply to the appellate arbitral tribunal, including establishment of the rules and manner of proceeding before that tribunal and ruling by that tribunal.
4. The rule specified by the parties that the arbitration proceeding is to include the possibility of appealing against the arbitration award issued at the first instance undoubtedly falls within the group of fundamental rules for purposes of Civil Procedure Code Art. 1206 §1(4). Violation of that rule by resolving the dispute at only one instance is a violation that could affect the result in the case, because the appeal could result in a different resolution.
5. Under the circumstances of the case, there was a violation of Civil Procedure Code Art. 1206 §1(4) by considering the dispute and issuing an arbitration award at only one instance, contrary to the rule agreed by the parties of arbitration proceedings at two instances.