PNG Corporation designs and builds roller coasters for amusement parks. At the end of 20x1, managers estimated overhead costs for 20x2 of $150,000 based on expected production of 5 roller coasters (5 jobs) using 5,000 labor hours each. Actual overhead costs for 20x2 were $170,000. PNG actually designed and built 6 roller coasters (6 jobs) with the following direct labor usage and overhead costs: Actual Overhead Cost actual Labor Hours The Big Dipper (job 1) $28,000 3,500 The Ultimate Scream (job 2) 35,000 4,000 Loop Me (job 3) 27,000 5,000 The Screaming Chicken (job 4) 40,000 2,500 You Dont Know Coasters (job 5) 25,000 6,000 Old Faithful (job 6) 15,000 4,500 Assume PNG uses a normal costing system with the number of labor hours as the overhead allocation base. a. Calculate the allocation rate for 20x2. b. Calculate the total corporate over- or underapplied overhead (specify which) for 20x2.