I am using the Mapquest API to report the shortest distance between two locations. This distance is used in our mileage reimbursement calculation. However, I have noticed that Mapquest.com reports a different mileage than the API. From: 3800 Anglin Dr, Fort Worth, TX 76119-2182 To: 800 Mercedes St, Benbrook, TX 76126-2527. Mapquest reports: 16.9 miles and the API reports 13.88 miles. What accounts for this difference?