The standard factory overhead rate is $7.50 per machine hour ($6.20 for variable factory overhad and $1.30 for fixed overhead) based on 100% capacity of 80,000 machine hours. The standard cost and the actual cost of factory overhead for the production of 15,000 units during August were as follows: What is the maount of the factory overhead volume variance & what is the amount of the factory overhead controllable variance?