computed on an estimated 8,000 direct labor hours per month and is $9 per direct labor hour, whereas the predetermined variable overhead rate is $3 per direct labor hour. Note: In answering the following questions, do not use negative signs with your answers. b. Compute overhead variances using a three-variance approach. OH Spending Variance OH Efficiency Variance Budget at Actual - Budget at Standard = OH Efficiency Variance $0x$0x=$0x c. Compute overhead variances using a two-variance approach. computed on an estimated 8,000 direct labor hours per month and is $9 per direct labor hour, whereas the predetermined variable overhead rate is $3 per direct labor hour. Note: In answering the following questions, do not use negative signs with your answers. b. Compute overhead variances using a three-variance approach. OH Spending Variance OH Efficiency Variance Budget at Actual - Budget at Standard = OH Efficiency Variance $0x$0x=$0x c. Compute overhead variances using a two-variance approach