My speed was between 60-70 mph on the said trip with AC on. This is only one observation and I started this thread to see what others will observe using the same method. At this stage I think its a wait and see game, like any experiment, it will take time to gather the data and prove or disprove that this was just an outlier observation. As said before, I did a SC trip and the truck only managed about 22mpg using the same method. So for the OBC to show 29.7 is a significant improvement. Lets see what others report but its worthwhile for the X35i owners to try this.