Airco Company is tempted to consider support department costs to be facility-level costs that do not need to be applied to products. Which of the following explains what is misguided about this approach?

1. Product costs may be inaccurate because straight-line depreciation on factory equipment is treated as a genera and administrative expense on the income statement.

2. Product costs may be inaccurate because support department services may be used more heavily by some products than others.

3. Product costs may be inaccurate because incorrect cost drivers are used.

4. Product costs may be inaccurate because direct labor and direct materials are not correctly accounted for in thu product costing system.