Question: We currently have the "Residential" checkbox checked (On) for all our UPS shipping methods. If a user enters a business shipping address for the ship to destination, will the system recognize that it is not a residential address and therefore not charge the extra residential pricing?
Answer: The integration with UPS is not able to look up the address to determine if it is residential or business. If you click on the residential rate box, all price lookups will be using the residential rate even if it is a business. It would be best to set each site to what you think would be most used. You can create one UPS shipping method for residential and another for business and then assign the appropriate one to the store.
"UPS Address Validation does not distinguish between residential and commercial addresses."