I'm skeptical too..... Especially with known bad TCM programming logic we're seeing more and more these days.
My Dad's 300, the first weekend he got it, Went ~550 miles to Columbus, OH. Doing *cough* the speed limit, air on, stopping from time to time
.....Got 31.5MPG. Did it in less then 1 tank. For a man who's been driving beat up B bodies and Panther platform vehicles for the past two decades, he was shocked as well.
..In a nearly two ton vehicle
...With a large-ish V6
....Not driven in a intentionally economical fashion
.....Not in a 3 cylinder Fiesta SFE
......In a LARGE AMERICAN RWD car
Why....
Because 8th gear.
After 1yr/40k of Livery use, its lifetime fluid fill seems to be holding up just fine