The High-low Method With Stepped Fixed Costs
　　Example:
　　The following data relate to the overhead expenditure of contract cleaners(for industrial cleaning) at two activity levels.
　　Square metres cleaned      12,750      15,100
　　Overheads                 $73,950     $83,585
　　When more than 14,000 square metres are industrially cleaned,there will be a step up in fixed costs of $4,700.
　　Required
　　Calculate the estimated total cost if 14,500 square metres are to be industrially cleaned.
　　Solution
　　Before we can compare high output costs with low output costs in the normal way,we must eliminate the part of the high output costs that are due to the step up in fixed costs:
　　Total cost for 15,100 without step up in fixed costs＝$83,585－$4,700＝$78,885
　　We can now proceed in the normal way using the revised cost above.
　　Units                            $
　　High output      15,100       Total cost      78,885
　　Low output       12,750       Total cost      73,950
　　2,350                        4,935
　　Variable cost＝$4,935/2,350＝$2.10 per square metre
　　Before we can calculate the total cost for 14,500 square metres we need to find the fixed costs.As the fixed costs for 14,500 square metres will include the step up of $5,000,we can use the activity level of 15,100 square metres for the fixed cost calculation:
　　$
　　Total cost(15,100 square metres)(includes the step up in fixed coss)  83,585
　　Total variable costs(15,100×$2.10)                                   31,710
　　Total fixed costs                                                     51,875
　　Estimated overhead expenditure if 14,500 square metres are to be industrially cleaned:
　　$
　　Fixed costs                    51,875
　　Variable costs(14,500×$2.10)  30,450
　　82,325