The only possible explanation I can find is that they have a central sorting facility in Indianapolis so all packages should go there. So for some reason the plane that went to indy must have had to stop in LA to either pick up more weight or pick up slack for others before going to Indy. And the package is scanned at every stop in case a loss occurs to know who is responsible. So in reality it ight have stoped anywhere before going to Indy and La just happened to be the stop in this particular case.