Both of those models are not flex fuel compliant per the window sticker or running the vin through www.etis.ford.com
, as they say unleaded fuel only. That's why the sticker mpg is 1 less as they had to be labeled according to the old standard.
As to the avg trip mpg it can't immediately go to where it was before, there is not enough data if you reset it while getting some specific mpg figure, ex. 40 but then you reset it the amount of data stored is zero initially, so it starts off low as it begins to average before converging on the average. That is actually what you'd want to see happen, not it instantly come back with the same number from before. We don't have an instant mpg feedback on the car, so if you're looking for instant data you'd need a scan guage type device.