Our UPS configured shipping rates are higher than the UPS website
Our account is configured to calculate shipping rates from our UPS account. However, we've been getting orders that the shipping is higher than what the UPS website is calculating. For example, when I estimate the shipping a package from Minneapolis, MN to Cary, NC the rate for 'UPS Ground' on the UPS website is $10.57. When our store website used the same shipping information, it charged our customer $17.65 for 'Ground' service.
Any ideas on what would be causing the difference in rates?