Inventory Valuation-

1. Why do relatively stable inventory costs across periods reduce the importance of management's choiceof an inventory costing method?
2. In a recent annual report, Kaiser Aluminum Corporation made the following statement in referenceto its inventories: "The Company recorded pretax charges of approximately $19.4 million because ofa reduction in the carrying values of its inventories caused principally by prevailing lower prices for alumina, primary aluminum, and fabricated products." What basic accounting principle caused KaiserAluminum to record this $19.4 million pretax charge? Briefly describe the rationale for this principle