I dunno, I do it all the time. I've changed my commute to driving through some towns instead of the interstate because my FE jumped this summer while driving that route. And that drive means lots of 25-40 miles per hour driving, and a couple of hills, and I spend a lot of time in EV mode. Either coasting, pushing EV sometimes to accelerate gas-free, or just trying to hold steady. When I push a little too hard and the ICE kicks in I go with it and give myself a bit of a "pulse" to keep the battery from dropping too low. *shrug* Works for me.