1.In the case of cancellation, refusal or total or partial non-payment, or where the price is reduced after the supply takes place, the taxable amount shall be reduced accordingly under conditions which shall be determined by the Member States.
2.In the case of total or partial non-payment, Member States may derogate from paragraph 1.
1.Where the factors used to determine the taxable amount on importation are expressed in a currency other than that of the Member State in which assessment takes place, the exchange rate shall be determined in accordance with the Community provisions governing the calculation of the value for customs purposes.
2.Where the factors used to determine the taxable amount of a transaction other than the importation of goods are expressed in a currency other than that of the Member State in which assessment takes place, the exchange rate applicable shall be the latest selling rate recorded, at the time VAT becomes chargeable, on the most representative exchange market or markets of the Member State concerned, or a rate determined by reference to that or those markets, in accordance with the rules laid down by that Member State.
However, for some of the transactions referred to in the first subparagraph or for certain categories of taxable persons, Member States may use the exchange rate determined in accordance with the Community provisions in force governing the calculation of the value for customs purposes.
As regards the costs of returnable packing material, Member States may take one of the following measures:
exclude them from the taxable amount and take the measures necessary to ensure that this amount is adjusted if the packing material is not returned;
include them in the taxable amount and take the measures necessary to ensure that this amount is adjusted if the packing material is in fact returned.