A company incurred overhead costs of $$8,400$ during the year and applied overhead to jobs at a rate of $$2$ per machine hour. This rate is determined based on estimated overhead of $$9,000$ and estimated total machine hours of $4,500.$ The company used $4,000$ machine hours during the month.

What is the correct entry to adjust for an immaterial amount of underapplied or overapplied overhead?