Sigma Company applies overhead cost to jobs on the basis of direct labour costs. Job A, which was started and completed during the current period, shows charges of $5,000 for direct materials, $8,000 for direct labour, and $6,000 for overhead on its job cost sheet. Job B, which is still in process at year-end, shows charges of $2,500 for direct materials and $4,000 for direct labour. Should any overhead cost be added to job B at year-end? Explain.