Following NEMMCO's rejection of the application for the proposed regulated South Australia–NSW interconnector, the ACCC was approached to undertake a review of the Customer benefits test. The ACCC engaged the firm Ernst & Young to help it conduct the review.
On 20 October 1999 the ACCC authorised changes to the National Electricity Code that included changes to replace the existing Customer benefits test for regulated interconnectors and network augmentations with a market benefit test (regulatory test).