Requirement $1.$ Using the$$ step$-$down method, allocate$$ support$-$department costs. Develop overhead rates per direct manufacturing$$ labor$-$hour for machining and assembly. Allocate the costs of the support departments in the order given in this problem. Use the allocation base for each support department you think is most appropriate. $($Round all indirect allocation rates to the nearest cent and all other computations to the nearest whole dollar. Round the overhead rates to three decimal$$ places.$)$