Where it is compulsory for a guarantee to be provided, the customs authorities shall fix the amount of such guarantee at a level equal to the precise amount of import or export duty corresponding to the customs debt and of other charges where that amount can be established with certainty at the time when the guarantee is required.

Where it is not possible to establish the precise amount, the guarantee shall be fixed at the maximum amount, as estimated by the customs authorities, of import or export duty corresponding to the customs debt and of other charges which have been or may be incurred.

Without prejudice to Article 95 where a comprehensive guarantee is provided for the amount of import or export duty corresponding to customs debts and other charges which vary in amount over time, the amount of such guarantee shall be set at a level enabling the amount of import or export duty corresponding to customs debts and other charges to be covered at all times.