Inventory valuation rules: differing scope and measurement obligations affect cost formulas and recoverable duties treatment. ICDS II, AS 2 and Ind AS 2 set differing scope exclusions and measurement rules for inventories: specific exemptions apply for construction WIP, producers' inventories measured at NRV, securities as stock in trade, commodity broker trader holdings, biological assets and agricultural produce at harvest. Cost assignment requires specific identification for non interchangeable items and permits FIFO or weighted average (with retail/standard methods allowed in limited circumstances). Changes in valuation methods require reasonable cause or qualify as accounting policy changes acceptable only when mandated or when more reliable and relevant. ICDS II includes duties and taxes in purchase cost even if later recoverable.