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http://help.sap.com/saphelp_nw70/helpda ... ameset.htm
You can use any number of characteristics in the query. Note, however, that the number of characteristics in the drilldown is restricted. An unlimited number of characteristics is permitted in the Free Characteristics area. Note, however, that the rows and columns can contain a maximum of 50 - <number of structures> characteristics only.
If the query does not contain a structure, a total of 50 characteristics are permitted in the rows and columns. If you use one structure, 49 characteristics are permitted, and with two structures, 48 characteristics are permitted in the rows and columns.