Parker Plastic, Inc., manufactures plastic mats to use with rolling office chairs. Its standard cost information for last year follows: Parker Plastic had the following actual results for the past year: Required: Calculate Parker Plastic's variable overhead rate and efficiency variances and its over-or underapplied variable overhead. (Do not round intermediate calculations. Indicate the effect of each variance by selecting "F" for Favorable/Overapplied and "U" for Unfavorable/Underapplied.) Answer is complete but not entirely correct