The fee as originally enacted was modified by the Customs and Trade Act of 1990 to make it consistent with U.S. obligations under GATT (the General Agreement on Tariffs and Trade) after a GATT panel had ruled that the original fee (a straight ad valorem fee) exceeded the cost of services rendered and was a tax on imports that discriminated against imports in favor of domestic production.
The fee that was originally enacted was modified by the Customs and Trade Act of 1990