In Appeal of Colambaarchchi (OTA Case No. 21017152; 2023-OTA-302), a California-based retailer was audited by the California Department of Tax and Fee Administration (CDTFA) for years 2016 through 2019. Upon audit, CDTFA determined that taxable sales went unreported. In calculating the extent of the underreporting, CDTFA used various indirect methods for different periods in the
