Cost behavior is the way prices are adjusted due to changes in costs . 71 . When managers plan , they may use cost behavior to decide how to change the mix of products to meet changing demand . 72 . Within the relevant range , fixed and variable costs behave differently . 73 . Unit variable costs vary with changes in productive output , whereas total variable costs remain constant . 74 . Unit fixed costs vary inversely with activity or volume . 75 . Theoretical operating capacity is the level at which management expects to operate during a normal business environment . 76 . Practical capacity and normal capacity are synonymous terms . 77 . The high - low method allows you to differentiate between fixed and variable costs when dealing with mixed costs . 78 . The point at which the total cost line intersects with the total revenue line provides information on the number of units that must be sold to break even . 79 . An insurance company pays its employees a commission of 6 percent on each sale . What is the proper classification of the cost of sales commissions ?