PLEASE EXPAND THESE SENTENCES/ANSWERS

Why is variable costing not used extensively in external reporting?

CAN YOU EXPAND THIS SENTENCE: Variable costing is not used extensively outside of the firm because absorption costing is required by GAAP and the IRS.

Why is absorption costing not used for CVP analysis?

CAN YOU EXPAND THIS SENTENCE: Absorption costing is not used in break-even analysis because it presents a classification of costs by function rather than by behavior. Without a behavioral classification of costs, it is impossible to predict how total costs change as volume changes.