I went back to look for my notes on this and this is what I experienced: The Fiat would use up about 30-40 miles of indicated range to go uphill less than 10 miles. But it would only regenerate 2-3 miles (of indicated range) on the downhill side.
The Fiat does have a range penalty for cold weather (it occasionally gets below freezing in the part of California I live in) and running the heater (one way; usually it's warm enough by the trip home). My wife still gets home with > 10%.
Keep in mind this is a 10yo car with an 80mi range; newer cars have bigger batteries.
Tell that to my colleague, who due to an accident near a major junction, took over an hour to travel a key couple of miles on his commute home from work yesterday.
Some journeys are "predictably unpredictable" during rush hour.
On flat land. Throw in hills and the number of projected range miles used by every real mile goes up very quickly.
I don't remember the specific numbers anymore, but we had two Fiat 500e cars and commuting over a mountain drained a lot of projected miles even though the climb was just a few miles.