As per case facts, the appellant sought a refund of fixed transportation charges for natural gas due to short supply, which the arbitral tribunal granted based on business efficacy and ... partial failure of consideration. The Single Judge set aside this award, finding the tribunal ignored a critical contractual waiver clause (Article 12.03) and wrongly extended the limitation period for provisional invoices. The appellant appealed, arguing the tribunal's findings were valid and Article 12.03 was void.The central legal question was whether the arbitral tribunal correctly applied contractual interpretation, business efficacy, and limitation principles, or if the Single Judge's intervention, based on patent illegality and ignoring a waiver clause, was justified.Finally, the Court found the arbitral tribunal exceeded its mandate by rewriting the contract to reduce fixed charges based on a misapplied business efficacy principle and without partial failure of consideration. The Court upheld the Single Judge's findings on the tribunal's failure to address Article 12.03 and the issue of limitation, concluding these constituted patent illegality, and thus dismissed the appeal.