Trip Computer MPG's Not Accurate

[jazzman]

My trip computer tells me that I average 28.3 MPG's, but my own calculations show that I'm getting pretty consistently 24 MPG's or so. What's up with that? Has Mazda set up the computer to be overly optimistic? I've got about 5k miles on mine, so the calculation should be pretty accurate at this point. Any other 2nd gen Speed owners notice the same thing?

 

[IRONBAR]

when im driving on the highways in texas i get anywhere from 28-34 mpg going at 70 mph

if i were u i would just get 3 averages of hwy driving and get their average. the mpgs are still better than my mustang and challenger so im happy