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.
Roosting Boxes for Birds. Roosting boxes are an important, all-season addition to backyard habitatsâand something thatâs easy to install in your yard. Roosting boxes protect birds from frigid winter conditions, driving rain and windy nights by offering shelter that they often canât find in a suburban setting.