Procedure
You choose menu option Goto -> Material group material (or "Materialgroup material maintenance") to call material maintenance. Here, youshould maintain the material group reference material in as much detailas possible. It represents not only a user-friendly input facility butalso a source of default material data for the whole material group.
If you entered new value-only materials, you also need to change therespective material group materials and/or hierarchy materials,particularly the respective (plant-dependent) tax classification.