D.H.T Problem

Everything is great here at Danny herman trucking get home when I ask 3 days off per 2 weeks friendly people etc etc but every time I get a load assignment the miles are way off I understand it zip to zip but it's not even close to that for example right now getting loading in three Rivers Michigan going to Bristol VA my assignment says 551 miles my GPS says 632 that's 81 miles off?? Google maps says 582 and it's mainly back roads etc stuff that trucks shouldn't be on I've just called complaining about it said to talk to my fleet manager tomorrow but I do this every trip wtf

 

And the trip before this one was 63miles off and it was only another 600ish mile trip...