The UPS API built into ShopSite will return the same rates displayed on UPS.com, but many factors can cause your store to display rates that appear to be incorrect.
The most obvious settings, which you have most likely already checked, would be:
• The weight of the product compared to the weight you are testing with at UPS.com
• The zip code you are shipping from (Commerce Setup > Shipping > UPS Configure > UPS User Info)
The customer's zip code
Note: The weights entered must be in pounds. If your products are smaller and normally weighed in ounces, be sure to use the pound equivalent. For example: 8 ounces = 0.5 pounds, 12 ounces = 0.75 pounds.
If those values all match and the rates are still not matching, there are additional settings under Commerce Setup > Shipping > UPS Configure that you would want to review:
UPS Delivery Type
Options: Residential or Commercial
• If you primarily ship to residential addresses you want to set this to Residential. Using a setting of Commercial will result in lower rates.
• When testing on UPS.com, this setting is called Destination Type and will listed below the ship to zip code on the form.
UPS Pickup Type
Options: Daily Pickup, Customer Counter, One Time Pickup, On Call Air, Letter Center
• Be sure to set this to the type of pickup you use when you ship your orders. Different pickup types will results in different rates.
• To edit this setting on UPS.com, you need to first select "Detailed Time & Cost" from the Quote Type menu on their form, then you can select how you ship the package on the Additional Information section of the form.
Weight & Dimensions
On UPS.com you can enter the weight into the Package Weight field and when you turn on "Detailed Time & Cost" from the Quote Type menu you can also enter the dimensions of your product. Make sure you are testing with the same weight on both your store and UPS, and if you have dimensions entered for your product you will need to enter dimensions on UPS.com to return an accurate rate.
Dimensions also complicate comparisons, because in ShopSite if you enter dimensions for a product the dimensions will be passed through the API for the rate calculation, but ShopSite will also calculate any product with dimensions as shipping on it's own. Therefore, if you order 2 items that have dimensions ShopSite will calculate 2 shipping rates and add them together. If you test on UPS.com with a total weight of both items you will receive a different rate then if you calculate them both separately on UPS.com.
Retail vs Contracted Rates
The UPS API in ShopSite will return the retail rates, which are the same rates that UPS.com will return. If you have a contract with UPS that provides you with a discount and you are testing with those rates through a program such as UPS Worldship you will not be able to accurately match rates for comparisons.
ShopSite has additional details on these settings available in their documentation here:
The UPS rates returned through the API in ShopSite will always match what UPS.com returns, when the same settings and values are used for comparisons. Once the UPS settings in ShopSite are configured to use the same options that are used when you ship your packages, the rates will match what you see on UPS.com.