Preble Company manufactures one product. Its variable manufacturing overhead is applied to production based on direct labor$-$hours and its standard cost card per unit is as follows:

Direct materials: $5$ pounds at $$11$ per pound $ $55$

Direct labor: $3$ hours at $$12$ per hour $36$

Variable overhead: $3$ hours at $$7$ per hour $21$

Total standard cost per unit $ $112$

The planning budget for March was based on producing and selling $21,000$ units. However, during March the company actually produced and sold $26,600$ units and incurred the following costs:

Purchased $154,000$ pounds of raw materials at a cost of $$9\mathrm{.}50$ per pound. All of this material was used in production.

Direct laborers worked $63,000$ hours at a rate of $$13$ per hour.

Total variable manufacturing overhead for the month was $$510,930.$

$15.$ What is the variable overhead efficiency variance for March?