Disadvantages of Flexible Budgeting
Though the flex budget is a good tool, it can be difficult to formulate and administer. Several issues are:
Many costs are not fully variable, instead having a fixed cost component that must be derived and then included in the flex budget formula.
A great deal of time can be spent developing step costs, which is more time than the typical accounting staff has available, especially when in the midst of creating the more traditional static budget. Consequently, the flex budget tends to include only a small number of step costs, as well as variable costs whose fixed cost components are not fully recognized.
The flexible budget model usually only works within a relatively limited revenue range; the budget analyst is unlikely to spend the time developing a more wide-ranging model if it is considered unlikely that outlier revenue amounts will be encountered.
There may also be a time delay between when there is a change in revenue and when a supposedly variable cost changes. Here are several examples:
Sales increase, but factory overhead costs do not increase at a similar rate, since the sales are from inventory that was produced in a prior period.
Sales increase, but commissions do not increase at a similar rate, since the commissions are based on cash received, which has a 30-day time lag.
Sales decline, but direct labor costs do not decline at the same rate, because management elected to retain the production staff.
Given the considerable amount of time required to maintain a flexible budget, some organizations may instead opt to eliminate their budgets entirely, in favor of using short-range forecasting without the use of any types of standards (flexible or otherwise). An alternative is to run a high-level flex budget as a pilot test to see how useful the concept is, and then expand the model as necessary.