In case of conflict between a rule of procedure promulgated by a Constitutional Commission and a Rule of Court, which prevails?

In case of conflict between a rule of procedure promulgated by a Constitutional Commission and a Rule of Court, the rule of the Commission should prevail if the proceeding is before the Commission; but if the proceeding is before a court, the Rules of Court prevail. (Aruelo vs. Court of Appeals, G.R. No. 107852, October 20, 1993)