Section 5(5)(d) in The West Bengal Electricity Regulatory Commission (Terms and Conditions of Tariff) Regulations, 2011
(d)Where the actual cost incurred on a capital expenditure project is lower than the approved original project cost, the Commission shall, after due scrutiny, permit the resultant savings in interest on loan capital during the construction period of such project to be dealt with in the manner specified in these regulations. Scrutiny of the original project cost shall be limited to the reasonableness of the capital cost, financing plan, interest during construction stage, use of efficient technology, economic use of resources, need to optimize investment and such other matters for determination of tariff.