The procedure aims at not burdening import goods with the payment of duties, with a view to their re-export after inward processing. If therefore the regime ends with the desired outcome (Re-export of compensating products) no duty is due (Suspension system) or duties paid can be reimbursed (Refund system).

NWhere a customs debt arises for the goods placed under the procedure with the suspension system (for example, if the procedure is discharged with release for free circulation), import duties and other duties under suspension are due.

Generally, they must be paid on the basis of the taxation elements specific to the import goods, as determined at the time of placing the goods under the procedure.

However, under certain conditions and for specific compensating products indicated in Annex 75 of the Implementing Provisions of the Community Customs Code, their own tariff treatment is applicable, instead of that of the goods from which they were obtained. These are, in principle, scraps, residues, by-products or secondary compensating products deriving from processing operations; in order for the above treatment to be applicable, it is in any case necessary to have re-exported, for a corresponding part, the main compensating products.

In order to proceed with taxation, the use of the imported goods in obtaining the compensating products must be taken into account and therefore the fixed rate of return; furthermore, the criteria for the distribution of imported goods in compensating products (quantitative key method and key value method) are established by Community legislation.