older car values

Is it more reliable for older values than late model? Because they are 30% too high where I live for late model stuff. I used to go by Old Cars Price Guide, but last time I checked, they were out of touch as well.

Edit: That 30% is for the kind of cars I buy to drive daily: 10 year old slightly above average mile eurotrash. They simply HAVE to be more accurate for newer cars, but I still hear they are on the high side.