Merchant category code
Restaurants qualify for specific interchange schedules under MCC 5812 for eating places and 5814 for fast food. Entities boarded under a generic retail or catering code pay materially more on identical transactions.
Check the MCC on each merchant statement, per entity, not per brand. Chains that grew through acquisition routinely carry two or three different codes across their locations, and the misclassified group is invisible in blended reporting.
Least-cost debit routing
Durbin routing rules let a PIN-eligible debit transaction travel over any enabled network. Each network prices differently, and the default configuration on most terminal deployments picks one and stays there.
Enabling least-cost routing at the processor and terminal level typically recovers 10-20 basis points on chains where debit is 30% or more of tender. Verify by pulling a month of transaction-level detail and confirming routing varies by transaction rather than sitting on one network.
Level 2 and Level 3 data
Corporate and purchasing card transactions qualify for reduced interchange when the transaction carries tax amount, customer code, and line-item detail. The POS almost always supports the fields; the integration almost never populates them.
This matters most for catering, large-party, and business-district locations where commercial card penetration is high. It is a one-time integration change captured permanently.
Downgrades: the fourth lever
A transaction that fails to qualify for its target interchange category downgrades to a more expensive one. Common causes are late settlement past the batch window, missing address data on keyed transactions, and tip adjustments processed after authorization windows close.
Downgrades look like interchange on a statement, so they survive every rate negotiation. Ask your processor for a downgrade report by reason code and by location - the stores that stand out are usually a settlement schedule problem, not a card mix problem.
Sequencing the work
Audit MCC per entity, then pull a downgrade report by reason code, then enable least-cost routing, then scope Level 2/3 population with the POS vendor. Baseline your effective rate per location before any change so the recovery is measurable.
On $100M of card volume, moving from 3.0% to 2.5% through configuration alone is $500K a year - available before any discussion of cash discount, and independent of it.
Takeaways
MCC, debit routing, Level 2/3 data, and downgrades are configuration - not negotiation.
Chains grown by acquisition often carry misclassified MCCs invisible in blended reporting.
Baseline effective rate per location before changing anything, or the recovery is unprovable.
Related reading
How Restaurants Eliminate Credit Card Processing Fees: The Complete Cash Discount GuideCash Discount vs. Surcharging vs. Dual Pricing: Which Model Fits Your RestaurantHow multi-unit restaurants overpay 60 to 80 bps on card processing