IOS mail track shipment option issue

In IOS mail on my both my iPhone and iPad as well as on my MacBook with Mail 9.3 on El Capitan, whenever I try to use the track shipment option with the embedded tracking number, it always take me to the United States Postal Service tracking site for packages that are actually being shipped by United Parcel Services...which of course results in tracking number not found. This seems to happen every time a package is being sent United Parcel Service. Is anyone else having this issue? IOS is at current release on both devices and El Capitan is at current release on MacBook.