Definitions for "flexible budget"
A set of revenue and expense projections at various production or sales volumes....
A budget that shows how costs vary with different rates of output or at different levels of sales volume and projects revenue based on these different output levels.
A budget which is designed to change in accordance with the actual level of activity achieved.
Keywords:  better, analysis, tool
a much better analysis tool
a plan which provides estimates of what costs should be for any level of activity within a specified range