An activity-based costing system that is designed for internal decision making will not conform to generally accepted accounting principles because: under activity-based costing the sum of all product costs does not equal the total costs of the company under activity-based costing manufacturing costs are assigned to products activity based costing has not been approved by the United Nation's International Accounting Board activity-based costing results in less accurate costs than more traditional costing methods based on direct labor-hours or machine hours