Reconcile a card settlement report to detect interchange downgrades caused by missing Level 2/3 line-item data

Steps

1. Pull the processor or network settlement/interchange-detail report for the period and extract the actual interchange category each transaction cleared at
2. Compare the cleared category against the category the transaction should have qualified for given the line-item data (tax amount, PO number, commodity code, etc.) your system submitted with it
3. Flag transactions that cleared at a lower, more expensive tier than expected as downgrades, and separately tag the specific missing or malformed field that most likely caused each one
4. Correlate downgraded transactions back to the originating integration or merchant channel so recurring root causes (e.g., a code path that never sets tax amount) can be fixed at the source instead of only reported after the fact
5. Track downgrade cost as a recurring metric (dollars lost per period) so engineering fixes can be prioritized against their financial impact