(25)Where Member States opt for a maximum level of fines set in fixed amounts, such levels should be laid down in national law. The highest levels of such fines should apply to the most serious forms of criminal offences defined in this Directive committed by legal persons of financial strength. Member States should be able to determine the method of calculation of those highest levels of fines, including specific conditions therefor. Member States are invited to regularly review the levels of fines set in fixed amounts having regard to rates of inflation and other fluctuations in monetary value, in accordance with procedures laid down in their national law. Member States that do not have the euro as their currency should provide for maximum levels of fines in their currency that correspond to the levels determined in this Directive in euro on the date of its entry into force. Those Member States are invited to regularly review the levels of fines also with regard to the development of the exchange rate.