Audit your mileage run: How Delta's miscalculation almost cost me Diamond Medallion status
Last week I flew from New York's John F. Kennedy International Airport (JFK) to Copenhagen Airport (CPH) on Delta Air Lines.
The trip wasn't a mileage run per se — I was meeting my cousin and a friend for a short trip — but I needed the Medallion Qualification Dollars to keep my Diamond Medallion status. After flying this trip and factoring in my other year-end travel, I will be at just more than 15,200 MQDs for the year.
However, a miscalculation in Delta's system shorted me 273 MQDs. If the mistake had gone unnoticed, it would have cost me my status for 2023.
See, when I landed back in New York, Delta credited my account 593 MQDs even though my ticket cost about $954. I wasn't expecting to earn MQDs on all of that spending — MQDs are only earned on the ticket's base fare and carrier-imposed surcharges, commonly dubbed "YR" — but I knew something was off.
I checked an elite status tracking spreadsheet I maintain and quickly confirmed I should have received 866 MQDs for my JFK-CPH-JFK itinerary. According to my receipt, the ticket had a base fare of $266 and $600 in carrier-imposed surcharges. This brings me to my missing 273 MQDs. In turn, I was also shorted just more than 3,000 redeemable SkyMiles too, as my redeemable mileage earnings were calculated on the incorrect $593 base fare plus carrier-imposed surcharge.
Thankfully, this story has a happy ending. I called the Diamond Medallion line and explained the situation to the representative. He called the SkyMiles department, they noticed their error and the representative told me they'd recalculate earnings with the correct fare and surcharges.
Roughly an hour later, my account was credited with the correct 866 MQDs and 9,526 redeemable miles, worth about $134 per TPG's valuations.
If I hadn't noticed this error, I could have lost my Diamond benefits over a simple mistake in Delta's system. Or, I would have had to panic-book a flight after finishing my holiday flights home and realizing I hadn't qualified for my status. Needless to say, that would not have been a cheap (or fun) endeavor right after the holidays.
Related: Quick Points: How and why you should regularly audit your loyalty accounts
Take my experience as a reminder to always check your loyalty account after you fly. Then, recalculate your earnings and ensure you received the proper number of redeemable miles and elite metrics. If you don't, you could leave miles and elite status on the table.
I also encourage you to build a spreadsheet that logs your flights throughout the year. I add all of my flights to this spreadsheet as I book them, alongside their Medallion Qualification Miles, MQDs and redeemable SkyMiles earnings. Then, I have a running number that adds all of them up and adds them to my current MQD balance. This helps me plan and audit my account quickly as I travel throughout the year, and it keeps me in the loop on how close I am to the next elite status tier.
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| 3X | Earn 3X Miles on Delta purchases. |
| 1X | Earn 1X Miles on all other eligible purchases. |
Pros
- Delta SkyClub access when flying Delta
- Annual companion ticket for travel on Delta (upon renewal)
- Ability to earn MQDs through spending
- Various statement credits for eligible purchases
Cons
- Steep annual fee of $650
- Other Delta cobranded cards offer superior earning categories
- Earn 100,000 Bonus Miles after you spend $6,000 or more in purchases with your new Card within the first 6 months of Card Membership and an additional 25,000 bonus miles after you make an additional $3,000 in purchases on the Card within your first 6 months, starting from the date that your account is opened. Offer Ends 04/01/2026.
- Delta SkyMiles® Reserve American Express Card Members receive 15 Visits per Medallion® Year to the Delta Sky Club® when flying Delta and can unlock an unlimited number of Visits after spending $75,000 in purchases on your Card in a calendar year. Plus, you’ll receive four One-Time Guest Passes each Medallion Year so you can share the experience with family and friends when traveling Delta together.
- Enjoy complimentary access to The Centurion® Lounge in the U.S. and select international locations (as set forth on the Centurion Lounge Website), Sidecar by The Centurion® Lounge in the U.S. (see the Centurion Lounge Website for more information on Sidecar by The Centurion® Lounge availability), and Escape Lounges when flying on a Delta flight booked with the Delta SkyMiles® Reserve American Express Card. § To access Sidecar by The Centurion® Lounge, Card Members must arrive within 90 minutes of their departing flight (including layovers). To access The Centurion® Lounge, Card Members must arrive within 3 hours of their departing flight. Effective July 8, 2026, during a layover, Card Members must arrive within 5 hours of the connecting flight.
- Receive $2,500 Medallion® Qualification Dollars with MQD Headstart each Medallion Qualification Year and earn $1 MQD for each $10 in purchases on your Delta SkyMiles® Reserve American Express Card with MQD Boost to get closer to Status next Medallion Year.
- Enjoy a Companion Certificate on a Delta First, Delta Comfort, or Delta Main round-trip flight to select destinations each year after renewal of your Card. The Companion Certificate requires payment of government-imposed taxes and fees of between $22 and $250 (for itineraries with up to four flight segments). Baggage charges and other restrictions apply. Delta Basic experiences are not eligible for this benefit.
- $240 Resy Credit: When you use your Delta SkyMiles® Reserve American Express Card for eligible purchases with U.S. Resy restaurants, you can earn up to $20 each month in statement credits. Enrollment required.
- $120 Rideshare Credit: Earn up to $10 back in statement credits each month after you use your Delta SkyMiles® Reserve American Express Card to pay for U.S. rideshare purchases with select providers. Enrollment required.
- Delta SkyMiles® Reserve American Express Card Members get 15% off when using miles to book Award Travel on Delta flights through delta.com and the Fly Delta app. Discount not applicable to partner-operated flights or to taxes and fees.
- With your Delta SkyMiles® Reserve American Express Card, receive upgrade priority over others with the same Medallion tier, product and fare experience purchased, and Million Miler milestone when you fly with Delta.
- Earn 3X Miles on Delta purchases and earn 1X Miles on all other eligible purchases.
- No Foreign Transaction Fees. Enjoy international travel without additional fees on purchases made abroad.
- $650 Annual Fee.
- Apply with confidence. Know if you're approved for a Card with no impact to your credit score. If you're approved and you choose to accept this Card, your credit score may be impacted.
- Terms Apply.
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