An activity-based costing system that's designed for internal decision making won't conform to generally accepted accounting principles (GAAP) because Question 17 options: A) under activity-based costing the sum of all product costs doesn't equal the total costs of the company. B) under activity-based costing manufacturing costs are assigned to products. C) activity-based costing hasn't been approved by the United Nations' International Accounting Board. D) activity-based costing results in less accurate costs than more traditional costing methods based on direct labor-hours or machine-hours