Gaining 20% range due to regen might be possible in the city test circuit, as it simulates 23 stops over a distance of 11 miles with an average speed of 21 MPH. If the same circuit was performed for the whole 250 mile battery range, that would be 523 stops... perhaps within the realm of belief in recapturing 11.2 kWh.
I'm not sure how the "combined" city/highway fuel economy is derived, but regen isn't going to add 40 miles of range in any scenario other than frequent stopping for the whole range of the battery.
City Test
Highway Test
https://www.fueleconomy.gov/feg/fe_test_schedules.shtml