Article 18 outlines the Authority's obligation to review taxpayer appeals and issue a decision within sixty days. Notification must be provided via a method ensuring proof of receipt. If the sixty-day period lapses without a response from the Authority, the appeal is legally deemed an 'implicit rejection'. If the Authority issues a decision and the taxpayer agrees with it, the tax assessment is finalized based on those revised terms. This timeline-bound process ensures that disputes do not remain unresolved indefinitely and defines the point at which an assessment becomes final following an internal review.