A company incurred the following production variances for product X during February: Direct material price variance Direct material quantity variance Direct labor efficiency variance Direct labor rate variance Variable overhead rate variance Variable overhead efficiency variance $10,000 Favorable $15,000 Unfavorable $20,000 Favorable $25,000 Unfavorable $12,500 Unfavorable $11,000 Unfavorable What is a possible reason for the labor rate variance based on these results?