From December 3, 2025 inclusive, in the registration of Export Declarations of the System AES The following rule will begin to be validated in the gross mass element: "If the number of packages in a goods item is zero, then the gross mass of that item must be zero." This rule has been listed for several months on page 102 of the AES Export Web Services Technical Guide, in the section "Goods Measure.Gross Mass", but its effective implementation will be on the aforementioned day.

This rule is consistent with the way of declaring the gross mass and net mass when goods items from different categories are packaged in a single shipment. In that case, in the item chosen to declare the package that is common to several items, the number of packages will be entered in the field: the number of actual packages; in gross mass: the actual gross mass that the package or packages weigh; and in net mass: the net mass that weighs exclusively the goods of said item. For a consignment whose goods are packaged in the packages of another consignment, the number of packages will be entered in the field: zero; in gross mass: zero, since zero packages weigh zero gross kilograms; and in net mass: the net mass that weighs exclusively the goods of said item.