Acme Companys production budget for August is 17,700 units and includes the following component unit costs: direct materials, $6.00; direct labor, $10.20; variable overhead, $6.20. Budgeted fixed overhead is $34,000. Actual production in August was 18,630 units, actual unit component costs incurred during August include direct materials, $8.00; direct labor, $9.60; variable overhead, $7.00. Actual fixed overhead was $35,700, the standard direct labor cost per unit consists of 0.5 hour of labor time at $20.4 per hour. During August, $178,848 of actual labor cost was incurred for 8,280 direct labor hours. Required: Calculate the labor rate variance and labor efficiency variance for August. (Indicate the effect of each variance by selecting "F" for favorable, "U" for unfavorable.)