Variable manufacturing overhead is applied on the basis of direct labor hours. The following data are available for October: 3,750 units of compound were produced during the month. There was no beginning direct materials inventory. The ending direct materials inventory was 2,000 ounces. Direct materials purchased: 12,000 ounces for $225,000. Direct labor hours worked: 5,600 hours at a cost of $67,200. Variable manufacturing overhead costs incurred amounted to $18,200. Variable manufacturing overhead applied to products: $18,375. The variable overhead efficiency variance for October is