So you’re getting 11 to 12 where the advertised mileage is 15. That’s pretty close. The transmission should be just getting settled in programming. I don’t see where the concern is. What did you drive before? How are your driving habits between what you used to drive, and this?
The magical MPG numbers are averages, with no particular relevancy if you are a hard driver, drive up hills alot, have a ladder rack on the back, or have a heavy foot.
There is a reason why these are selling cheaper lately. Gasolina es mucho espensivo!