As per case facts the Power Generator Respondent sought compensation and carrying cost at Late Payment Surcharge LPS rates from the Distribution Companies Appellants for a levy imposed by a ... public authority which the Generator claimed constituted a 'Change in Law' event under the Power Purchase Agreement PPA The Appellants appealed the Appellate Tribunal's decision arguing that the claim should fall under a different PPA clause that postpones the effective date of adjustment and that carrying cost at LPS rates wasn't due without a prior supplementary bill The question arose whether the levy constituted a 'Change in Law' under the PPA and from what date the financial consequences including carrying cost should apply Finally the Supreme Court held that the levy constituted a 'Change in Law' event effective from the date of the Notification not the date of the Tribunal's order and upheld the award of carrying cost at LPS rates rejecting the argument that a prior supplementary bill was a mandatory pre-condition for such payment