Advance ruling voidability protects revenue where rulings obtained by fraud or misrepresentation, with hearing required. Where an advance ruling is obtained by fraud, suppression of material facts, or misrepresentation, the Authority or Appellate Authority may declare the ruling void ab initio, causing all provisions of the Act to apply as if the ruling had never been made, provided the applicant is given an opportunity to be heard; the period from the ruling to the voiding order is excluded from certain limitation computations, and a copy of the order must be sent to the applicant and prescribed officers.