This Decision provides detailed rules for implementing the Federal Decree-Law No. 8 of 2017 on Value Added Tax. Specifically, Article 28 clarifies the calculation of the value of supply in cases involving discounts, subsidies, and vouchers. It establishes that a subsidy from the State is not treated as such if it is consideration for a supply. The Decision outlines the conditions for reducing the value of supply for discounts, requiring the customer to benefit and the supplier to fund it. It also specifies how to value vouchers, differentiating based on whether they are sold for consideration.