I'm going to guess, yes, it will affect MTE by a similar factor. The thing is, the typical 4% to 5% error is peanuts compared to other, much larger, sources of error. Not least of these is the assumption that your future MPG will be the same as the recent average. Don't forget that when it's most critical, when DTE is small, the absolute error (in miles) is also proportionally small. If it's 4% optimistic and that were the only error, that means when it calculates 500 miles to empty it's really 480 miles, but when it calculates 50 miles, it's really 48. If you're relying on that level of accuracy you're practically guaranteed to have problems. Don't forget that the DTE is shown in 10-mile steps and the change from 50 to 40 miles is a 20% drop; a difference of a couple of miles (4%) is swamped by this.Perhaps the systems aren't tied to each other but doesn't the car showing a higher than actual MPG overestimate the miles until empty reading?