Fashgasm 11.1.202015 on Clearly, the more units produced, the lower the cost per unit of these overhead processes. Area volume relationships: as a physical fact, if the volume of some vessel or container is increased to the cube of itself (i.e. a volume x is increased to x), the area enclosing it is increased only to the square of itself (i.e. an area y is increased to y). If the output capacity therefore depends on the volume while cost depends on the area, then cost increases less than proportionately to output. Fashgasm 11.1.202015 2016.