The EV mode button only works if 1) you have enough battery 2) the car is warmed up 3) you don't accelerate too hard 4) and only up to 25 mph. It may go a little higher with gentle acceleration but, not much. You can put the car in EV mode anytime by letting off the gas pedal at speeds lower than 45mph, assuming the car is warmed up and you have enough battery. I never really understood the need for a EV button.
I agree, and have only gotten value from the EV button during the summertime when instructing the system not to engage the ICE in startup. The ICE in startup is the single largest consumption of gas the car ever experienced. Otherwise, it is just as you say about using the gas pedal. Use the Eco Score screen and it is golden.
Try turning Eco mode off, I know it sounds counter productive, but when I use it here in Dallas,Tx I get worse milage. I have to step on the gas harder to not distrupt traffic to much. I realized the car was revving higher than need be, causing greater fuel consumption.
The limit is precisely that on regular 3rd gen Prius as well. One place you can always see this in Van, rolling down the hill (eastbound) at the beginning of Barnet Highway, going by the Kask Brothers Cement plant. I'd agree. There's a certain amount of pedal travel that's easy to control. For me that's "normal" mode; ECO requires exaggerated pedal travel to achieve average response, you need to really tromp it, and that's counterproductive. Perhaps telling: with the 2016 Prius I read (press release or review, not sure which) that all of the "modes" have been shifted, one modes worth, towards more aggressive. In other words: ECO pedal response is like 3rd gen normal, normal's like PWR. And PWR? Don't ask, lol.
