Mini-Exercise Variable overhead variances In addition to the information for Acme Company in Mia-Exercises 15.1 and 15.2. the standard variable overhead rate per unit consists LO 4,0 of 56 per trachine hour and each unit is allowed a standard of 1 hour of machine time. During August, S115,940 of actual variable overhead cost was incurred for 18,700 machine hours Required: Calculate the variable overhead spending variance and the variable overhead efficiency variance