Valera corporation makes a product with the following standards for labor and variable overhead: standard quantity or hours standard price or rate standard cost per unit direct labor 0.4 hours $ 21.00 per hour $ 8.40 variable overhead 0.4 hours $ 6.00 per hour $ 2.40 the company budgeted for production of 5,300 units in july, but actual production was 5,400 units. the company used 2,130 direct labor-hours to produce this output. the actual variable overhead rate was $6.10 per hour. the company applies variable overhead on the basis of direct labor-hours. the variable overhead rate variance for july is: