Hierarchy Exception Aggregation NGA and NHA 
Hierarchy exception aggregations NGA and HGA are special aggregation rules for hierarchies with postable nodes. Postable nodes are hierarchy nodes that do not simply aggregate their child nodes but also have a value of their own that is added to the aggregation. It is possible to display the own value of a postable node as the child of this node so that the display corresponds to that of a normal hierarchy.
Example
In the following example there is a normal hierarchy node (node 1) and a postable node below it with a value part (page 1) of its own. Page 1 can be displayed a the child of the postable node. Apart from this the postable node has an actual child (page 2). The following graphic shows the result of an aggregation of type SUM.
If output aggregation NGA is applied to key figure 1, this produces the result that the postable node only has the value of its own value part, that is, from page 1. The node on a higher level also only includes this value part so that node 1 of the example above also displays the value of page 1. This means that NGA ensures that a postable node does not aggregate its own value and that of its children, but only displays its own value part.
NHA works in a similar way: This aggregation type also ensures that nodes with a postable value part (but which only aggregate the values of their children) are displayed as NULL. This means they have no value if they are not postable nodes.
The rules are simple with regard to the special values NULL, ERROR, or NOP. NGA and NHA do not specify any aggregation rules, they only dfine that the postable part of a postable node is indluded as the only value in the standard aggregation. Only the value of a postable node is included for the hierarchy exception aggregations NGA and HGA, irrespective of whether it is a special value or not. The rules of the standard aggregation SUM, MIN, and MAX are applied accordingly.