Allocated fixed costs, often called common costs, are costs that are not traceable to a particular product, service, product line, or segment. They are never relevant because the costs are assigned to a number of products.llocated fixed costs, often called common costs, are costs that are not traceable to a particular product, service, product line, or segment. They are never relevant because the costs are assigned to a number of products.
Definition of roost. 1  1a : a support on which birds restb : a place where winged animals and especially birds customarily roost. 2  2 : a group of birds roosting together.
a pole or rod, usually horizontal, serving as a roost for birds. 2. any place or object, as a sill, fence, branch, or twig, for a bird, animal, or person to alight or rest upon. 3. a high or elevated position, resting place, or the like. 4. a small, elevated seat for the driver of any of certain vehicles.