What's your idle gph? Mine's about 0.3. Compare that to the gph of EOC = 0. Now apply that difference to half of the drive that I EOC. It makes a big difference.
Estimated 0.3 * (0.5 hour drive * 1/2 (eoc percent)) = 0.075 gallons
Regular commute = 0.14 gallons (10.5 mi / 75 mpg)
0.14 + 0.075 = 0.215
10.5 / 0.215 = 48.8 mpg if I engine-on-coast instead.
That's a 35% drop!