Assuming that direct labor is a variable cost, the primary difference between the absorption and variable costing is that: variable costing treats only direct materials, direct labor, the variable portion of manufacturing overhead, and the variable portion of selling and administrative expenses as product cost while absorption costing treats direct materials, direct labor, the variable portion of manufacturing overhead, and an allocated portion of fixed manufacturing overhead as product costs. variable costing treats direct materials, direct labor, the variable portion of manufacturing overhead, and an allocated portion of fixed manufacturing overhead as product costs while absorption costing treats only direct materials, direct labor, and the variable portion of manufacturing overhead as product costs. variable costing treats only direct materials, direct labor, and the variable portion of manufacturing overhead as product costs while absorption costing treats direct materials, direct labor, the variable portion of manufacturing overhead, and an allocated portion of fixed manufacturing overhead as product costs. variable costing treats only direct materials and direct labor as product cost while absorption costing treats direct materials, direct labor, and the variable portion of manufacturing overhead as product costs