1.Although expenses in the past have varied erratically, such behavior should not be viewed as normasive for the future. Many expenses may have been erratie because of poor control, waste, inefficiency, faulty accounting, and unwise management decisions. 2. Many expenses are subject to discretionary management policies. The fact that policies were changed during the period under analysis may have caused erratic expense vriations. These “policy variations” can be isolated and should be taken into consideratim in estimating expense vanability foe the future 3. Past expenses that have been erratic will generally "shape up" when budgeted and controlled. Exhibit 10-11 shows this effect in an actual case. 4. Actual costs that are dissimilar should be classified separately in the accounting system. For example, certain indirect labor costs may vary in proportion to output; however, management policy may require that any indirect-labor employee laid off will be paid two weeks severance pay. This severance pay should not be cassified as a normal indirect labor expense, but as a special expense. Mixing the two different expenses in one account would tend to destroy the pattern of variability for each account. 5.Flexible budget procedures do not necssariy require the use of straightine relatonships for all expenses. 6.Certain expenses in all companies will be influenced by spacial factors, some external and some internal, which may require special consideration for planning purposes. The number of such expenses is much lower than is commonly supposed. 7. Perfect linearity is not required for practical considerations. Approximate linearity usually is sufficiently accurate if sound management decisions and control persist. 8.Industry surveys reveal numerous cases where expense variability related to activity levels of output or activity is identified on a practical and useful basis. 9. The type of operations engaged in by the company determines the extent to which expense activity relationships may be resolved.