Article 17 outlines the framework for voluntary tax registration for any Person not otherwise obligated to register. A Person may apply under two conditions. The first is a retrospective test: if, at the end of any month, the total value of their taxable supplies (as referenced in Article 19) or incurred expenses subject to tax over the previous 12-month period has exceeded the Voluntary Registration Threshold. The second is a prospective test: if the Person anticipates that the total value of such supplies or expenses will exceed the Voluntary Registration Threshold within the upcoming 30-day period.