That lag creates a dangerous window where customers expect lower prices before businesses have realized lower costs. Contracts, supplier agreements, fuel surcharges and inventory all determine when lower commodity prices actually show up in operating costs. Until those inventories are depleted, lower commodity prices don't translate into lower production costs. Customers see falling oil prices in the news, but most don’t see the lag between commodity markets and actual production costs. The challenge is managing the period between lower commodity prices and lower operating costs.