Warp Manufacturing Corporation uses a standard cost system for the production of its ski lift chairs. Warp uses machine-hours as an overhead base. The variable manufacturing overhead standards for each chair are 1.2 machine-hours at a standard cost of $18 per hour. During the month of September, Warp incurred 34,000 machine-hours in the production of 32,000 ski lift chairs. The total variable manufacturing overhead cost was $649,400. What is Warp's variable overhead rate variance for September