Reflective to your stats and informative post, my 2006 E320 CDI yields 31 to 33 mpg Expressway, and 24 mpg City. The. onboard computer DIC metering is 10% OVER actual mpg.
Cross Country Interstate driving yields 41 mpg, MINUS 10% for actual mpg.

My 2017 Chevrolet Corvette yields a solid 31 mpg, HWY / 18 mpg CITY. Cumulative from 0 miles since new; 18.7 mpg. My Corvette has gained 25% in value since the vehicle shortage began. That's what a dealer will give you before marking it up for sale.

It doesn't really matter how high your HWY only mpg is, because the only thing that matters are the particular vehicle's cumulative miles driven, and total dollars spent, to get there.

I'm not sure a $50K+ plus vehicle is in any way topical in the conversation to squeeze out a few cents per mile in fuel costs, for very limited vehicle use. It's a non-issue to me.

The EV Mercedes captioned above @ what, $130K, probably isn't worth calculating it's cost factor to miles driven, because of it's extreme cost to purchase. Or so it seems to me...

My maintenance, depreciation, interest, and property tax ($0 in Floriduh), or "MDI&P" has been $0.825/mile for the first three years and 25,666 miles. Fuel cost was another $0.100/mile.

Fuel economy is more of a tree-hugger thing than a money-hugger thing. That's why my future 330i is still at least 2.5 years off in the future. I'm going to keep my 535i at least until it's ten years old. A new 330i's better MPG wouldn't even make a dent in the additional cost of owning it.

When I buy a new car, I consider what will be "acceptable" MPG ten years in the future. That's why I have a 535i instead of an M5. The 535i's at 25.8 MPG since new, and it gets 29 MPG on the interstate. It replaced a 2002 M3 that got 21.3 MPG since new and 24 MPG on the interstate.

Without replacing the 535i now, we reduce our fuel use by making the X3 our primary car. If we're going somewhere together, we take it. If I'm going somewhere alone, but Frau Putzer's staying home, I also take the X3. Doing this will also put more miles on the X3's original tires before they age-out (six years of use). It will also conserve my irreplaceable manual-transmission 535i.

We did a lunch run in the 535i this week, together, because it was raining and the X3 was washed the previous day and tucked away clean. Frau Putzer was *****ing about having to climbing in and out of the 535i.

The 535i and X3 can both reliably do 500 miles of interstate driving. That's about a full day of leisure driving. I can get where I'm going for the night and fill up the next morning. With the M3, I was lucky to get 350 miles out of a tank of gas.

One of my militant tree-hugger relatives was ragging on me about my M3 at a Putzer family reunion. I told her the M3 used less gasoline than my Honda Civic. After she came down from the ceiling, I explained that was because I drove the Civic more than I did the M3.

There's a reason they call Honda Civics "Civics" instead of "Interstates." My 1997 Civic got pretty much the same MPG in town and on rural interstates, 33 MPG. It was really straining at 80 MPH with the AC on.

I love talking cars, SUVs, etc. You can get caught up in the nuts and bolts, and dollars and cents very easily. At the end of the day, you've got to enjoy the ownership experience of what you drive. If you can afford it that is. My current mechanical interest has been devoted to finding a one owner 2019 or up, Ford GT to purchase. So far only one owner has contacted me. He's priced a little more than I'm willing to pay right now. I'm hoping my contacts out there will get me one reasonably priced. In the meantime, I'm waiting to see if Chevrolet will put a MT in the new C8. The Mercedes is possibly FS as well. Not really interested in anything else automotive wise right now.

I did another Sam's Club-Cracker Barrel-Wendy's run last night in the X3. I caught most of the traffic lights green, and the X3 was already warmed up when I started. I was playing my "hyper-mile-ing" game. Parking at Sam's Club, the displayed MPG was 40.5. So, the real MPG was right around 40.

Sometimes, I get my green veggies at Cracker Barrel, and grab a cheeseburger on the way home.

Sam's Club was rationing spring water and purified water, limit of three cases. When we get down to six cases (20 liters/case), I buy six more. I keep a strategic stockpile of a lot of non-perishable consumables, and stock up when they're on sale. During the lockdown-smackdown and after the 2018 CAT 5 hurricane, we never ran out of water, toilet paper, cat food, cat litter, cat treats, etc.

Waiting in the Wendy's drive-thru line trashed my total trip MPG. It was only 30 by the time I got home.

So, what's your cumulative (ACTUAL) mpg of the total miles on that BMW SUV?

My 2017 Corvette routinely registers between "51 and 99 mpg." LOL!

The actual (gas pump) fuel economy since new is 25.17 MPG after 30,122 miles That's because it's Frau Putzer's car, most of the places she goes are less than two miles away from the house, she doesn't use EcoPro, and she drives like a chimpanzee.

Our 28-mile run to dinner last night yielded 30 MPG with me driving. I had steak fajitas. Mmmmm.

My 535i's since-new, actual fuel economy is 25.85 MPG after 73, 952 miles. My Chevy Cobalt's is 28.23 MPG for 125,146 miles, but that car racked up a lot of highway miles when I was working. My E46 M3's was 21.18 MPG for 114,554 miles, also with a lot of highway miles.

New BMW's track four fuel economies: since new, trip (reset if the car's shut off for over four hours), since refueling, and "Individual" (resettable by the user). Our two current BMW's only track two MPG's: On Board Computer and Trip Computer, both user-resettable. I reset the On Board MPG when I refuel.

Knowing the error if the displayed MPG's, I can predict how much fuel I'll need within 0.2 gallons. That lets me blend 1/3 87 AKI and 2/3's 93 AKI to make my own BMW-recommended 91 AKI, saving about $4/fill-up.

I pump in the 93 AKI first, so I get all the 93 AKI I pay for, and I don't leave any free-upgrade 93 AKI in the gas pump hose for the next guy.