When product costs are used for decision-making, what assumption is most likely to distort the decisions

Moody corporation uses a job-order costing system with a plantwide predetermined overhead rate based on machine-hours. at the beginning of the year, the company made the following estimates: machine-hours required to support estimated production 100,000 fixed manufacturing overhead cost $ 650,000 variable manufacturing overhead cost per machine-hour $ 3.00 required: 1. compute the plantwide predetermined overhead rate. 2. during the year, job 400 was started and completed. the following information was available with respect to this job: direct materials $ 450 direct labor cost $ 210 machine-hours used 40