 If the parts with variable consumption are just a few, like grease or the ink used to print product-labels, the consumed quantities can be assigned to product-independent cost centers at the withdrawal from stores (preproduction issuing) and can eventually be broken down afterwards to specific products or product groups, just like any other indirect or overhead expense.Difficulties maintaining correct inventories on shop floor may also appear if it is usual practice to use alternative materials and/or quantities without needing derogation.Therefore, in case of a more complex production system, it is a better approach to use a Manufacturing Execution System (MES) which gathers real production data and is able to deliver exact data to the accounting software or Enterprise resource planning-system where the goods issue is recorded.