@W0LFB3AT5:

Even with my last car, a 1.0L 3 cylinder turbo Focus with the 6spd manual (with two OD top gears, and 50 HP less than yer Benz), I was only able to wring out about 42-43MPG combined driving gently

... and I rarely drive gently; if I did in my current truck, the adaptive learning transmission would drive like a sack of foreskins
(I rarely get better than 20MPG now, but it is a V6 4x4)