I’ve rarely been able to make mpg calculations worth the cost of changing vehicles. At various times in my career I’ve had gas cards, and then not. When I have the gas card I don’t care about mpg, and when I don’t I think k should sell the guzzler and get something else because now it’s in my dime. I’ve never been able to make the longer payments make sense.
That said I haven’t tried to do that math with a lease. Never leased a vehicle. Maybe it works out in that case.
I’d imagine the formula is similar.
One other thing I’ve often forgotten, eventually gas prices go back down again. Something to think about when you’re doing that math.