I recently flew CO and was earning DL Skymiles for the flight. It was EWR-TPA and back. On my CO ticket, it represented that the mielage for the flight was 1,010 miles. However, when credited to my Skymiles account, it was registered as only 998 miles.

Anyone know why there is a discrepancy between what CO shows on the ticket and what is deposited into my Skymiles account both as miles and MQMs?