Why are separate prices charged for deliveries and deliveries to third parties, even if it concerns only one delivery/delivery?

With the delivery/delivery to third parties (order address not equal to delivery address) we assume a service to relieve the ordering person. We are concerned that the delivery arrives on time at the correct place, even if unexpected events should occur (incomplete address, prevention of accessibility, different letterbox labeling, etc.) In the case of delivery to the ordering person, we can assume that the information is correct and up to date.