What Discover Reason Code AW Means
Discover reason code AW — Altered Amount is a processing error dispute that occurs when the transaction amount settled was different from the amount the cardholder authorized at the point of sale or during checkout.
AW disputes commonly arise from tips added after authorization at restaurants, final amounts that differ from estimates (hotels, car rentals), or genuine processing errors where the wrong amount was keyed or submitted for settlement. Before responding, compare the authorized amount against the settled amount. If they differ without the cardholder's consent, accept the chargeback for the difference.
AW disputes have a low merchant win rate because the most common cause — a genuinely altered amount — is indefensible. Before contesting, confirm that the authorized amount matches the settled amount exactly. If there is any discrepancy, a partial credit for the difference is often a better outcome than a full chargeback.
Cross-Network Equivalent Codes
| Network | Code | Title | Notes |
|---|---|---|---|
| Discover | AW | Altered Amount | This page |
| Visa | 12.5 | Incorrect Transaction Amount | Visa equivalent for amount discrepancy disputes |
| Mastercard | 4834 | Point of Interaction Error | Covers processing amount errors |
| Amex | P01 | Unassigned Card Number / Incorrect Amount | Amex processing error code for amount disputes |
Common Trigger Scenarios
- Restaurant tip added post-authorization — The most common AW scenario: a customer authorizes a base amount, then a tip is added before settlement. If the final amount exceeds what the cardholder wrote on the tip line or expected, they dispute under AW.
- Hotel or car rental final charge differs from estimate — An estimated hold was authorized and the final charge exceeded the estimate without the cardholder's explicit consent. Hotels and car rentals should disclose final billing policies at check-in.
- Keying error during manual entry — A cashier manually enters the wrong amount — transposing digits or entering a different value than the purchase price. The settled amount doesn't match what the customer paid.
- Currency conversion error — For multi-currency transactions, a conversion error results in a different amount being billed than the cardholder expected based on the displayed local price.
- Surcharge not disclosed — A credit card surcharge or service fee was added to the final charge without being disclosed before the transaction was completed.
Key Deadlines & Timeframes
| Milestone | Timeframe | Notes |
|---|---|---|
| Cardholder Filing Window | 120 days | From the transaction date |
| Merchant Response Window | 30 days | From dispute notification; confirm with your processor for internal deadlines |
| Pre-Arbitration | 30 days | If Discover rejects representment, 30 days to escalate |
Evidence You Will Need
- Signed receipt with final amount — A receipt signed by the cardholder showing the complete transaction amount — including any tip or surcharge — is the strongest defense for AW disputes
- Authorization record matching settled amount — Documentation showing the authorization and settlement amounts are identical, with timestamps and authorization codes for both
- Tip policy disclosure — For restaurants, evidence that your tip policy is posted at the point of sale or on receipts, and that the tip line was visible on the receipt the cardholder signed
- Order record or invoice — The original order record or invoice showing the agreed-upon price matches the charged amount
- Customer communications — Any email or written communication from the cardholder acknowledging the total amount, such as an order confirmation showing the correct charge
Get the AW Response Templates
Our processing errors guide covers AW representment structure, tip dispute documentation, and how to present receipt evidence across all amount-discrepancy disputes.
Get the AW Response Templates →How Merchants Lose This Dispute
- Settlement amount does not match authorization — If the settled amount is higher than what was authorized — even by a few dollars — and you have no documentation of the cardholder's consent to the higher amount, the dispute will be lost.
- No signed final receipt — Charging a different amount than the initial authorization without a signed receipt showing the cardholder approved the final total is the leading cause of lost AW disputes.
- Undisclosed surcharges — Adding a credit card surcharge or convenience fee not disclosed before transaction completion is both an AW trigger and potentially a network rules violation.
- Tip amount exceeds signed receipt — If the tip amount entered into the POS system is higher than what the cardholder wrote on the tip line, there is no valid defense. Process the exact amount the customer wrote.
Response Framework Overview
- Compare authorization and settlement amounts. Pull both records. If they differ, assess whether a partial credit resolves the dispute more efficiently than a full chargeback response.
- Present signed receipt showing agreed amount. If amounts match, lead with the signed receipt showing the cardholder approved the total. This is the primary evidence for AW representment.
- Provide authorization record. Show the authorization approval matching the settled amount to demonstrate the amounts are consistent throughout the transaction lifecycle.
- Document disclosed policies. If the dispute involves a tip or surcharge, show that the policy was disclosed before the transaction was authorized.
Prevention Tips
- Print final receipts showing the complete amount — Always ensure cardholders sign a receipt that shows the complete final amount — base charge plus tip, taxes, and surcharges — before the transaction is processed.
- Match settlement to authorization exactly — Configure your payment system to only settle the exact authorized amount. Any post-authorization adjustments (tips, incidentals) should follow network rules for permissible overage amounts.
- Disclose all fees before authorization — Surcharges, service fees, and other additions must be disclosed before the customer authorizes. Post-authorization additions without consent are indefensible under AW.
- Train staff on tip processing — Restaurant staff should enter tips exactly as written on the receipt — never round up or estimate. A policy of entering the exact written tip amount eliminates the most common AW trigger.
Frequently Asked Questions
What is Discover reason code AW?
Discover AW (Altered Amount) is filed when the amount charged to the cardholder's account differs from the amount that was authorized or shown on the receipt at the time of purchase.
How do I win a Discover AW chargeback?
Win AW by producing a receipt or authorization record showing the cardholder agreed to the exact amount that was charged. If the amounts differ — even by a small amount — accept the chargeback or offer a partial credit for the difference.
What is the most common cause of AW chargebacks?
Restaurant tip adjustments are the most common cause. If a tip is added to a card after the initial authorization and the total differs from what the cardholder recorded, they may file an AW dispute.
Can I win an AW dispute if the tip was added after authorization?
Yes, but only if your tip policy is clearly disclosed, the final amount was within Discover's permissible tip overage, and the cardholder signed a receipt showing the total including tip. Tip disputes without a signed final receipt are very difficult to win.