The key dillerence between a contribution margin income statement and traditional GAAP income stabement is that a GAAP income strtement

reports $5$C$-$A expenses, while a contribution margin income statement reports faed cests.

includes both feed and variable coits while only wariable costs are included on a contribution in argin income statement:

holudes product and period couts while a contribution margin income Matement exhades period conts.

reports costs by function, while a contribution margen income statement reports costs based on behavior.