The only thing I'm able to understand from your math is that because one vehicle with a different powertrain got 3mpg above its EPA rating, yours should too (terrible assumption).
100,000 miles at 24mpg is 4166.7 gallons. At 28 mpg it is 3571.4 gallons. Difference of about 600 gallons. At $3.50/gallon you save $2,100 over the course of 100,000 miles by buying the 2.0L 4 cyclinder over the 3.5L V6. Your math calculating that it would pay off in such a short time span is based on some bad assumptions.
No car manufacturer rates their fuel economy at 75 mph. Try going 55 to 60 mph with an empty car. You don't seem to understand that the ratings are under "ideal" conditions. Weather, passengers, speed, and a multitude of other factors that are difficult to simulate in a laboratory all work to your detriment.
1. When one goes car shopping, doesn't one look at the EPA ratings to compare one vehicle to another even if they are different brands and different drive trains? So why shouldn't an Ex w/2.0L rated at 28 mpg hwy get better fuel economy than an EX V6 AWD rated at 23 mpg hwy under similar conditions?
2. I assumed that, over ~5 year time span, that big oil will be screwing us with gas prices over $4/gal. When we bought our Ex the prices were close to $4/gal.I believe that Ford fudged on the EPA tests on the Ecoboost Ex just to have the claim of 28 mpg & "Best in Class fuel economy"; just like they did on ALL of their hybrids.
3. True, but if you check out the EPA test cycles they don't just cruise at a steady speed for the duration of the test. They speed up & slow down & stop. We test drove an Ex w/V6 before buying (no 2.0L was available) and drove it for several miles at 70-75 mph & it got ~24 mpg, so our assumption was the 2.0L would do better than that.
For the record, I have checked the EPA website and others and fully understand the factors affecting fuel economy and how EPA tests are done by the manufacturer on a chassis dynamometer, and that a manufacturer can use the testing results of another vehicle with the same drive train for the results of that vehicle. We do know several people with Ex V6 who get their EPA hwy mpg at 70-75 mph, just as the one did on our test drive. I don't think it's unreasonable to expect the 2.0L to do better just as Ford claims it will.
Also, my first letter to Ford was 2.5 pages long with 5 pages of supporting documentation, so there was a lot more detail than what I have provided on this thread. If I had included all of that info, either people wouldn't read it all or would just cherry-pick some facts and go from there.
What I would really just like a respectful response from Ford, not just another form letter or contending with their system designed to discourage & frustrate a customer. My purpose in starting this thread was to let others know how Ford's system for issues with their vehicles is one of avoidance and discouragement and frustration that it is for resolution. It's kind of funny how Ford recently sent us a promotional flyer that stated "To us, you're more than a Ford owner... you're a valued part of our community." What I want to say to Ford is "Is this how you treat valued parts of your community? If so, I guess I'll be moving."