I actually get much better gas mileage using the IMA assist more aggresively but during the proper times in shorter bursts. For instance if I accelerate very slowly from light to light, you stay at low mpg situation, slowly losing charge the entire time. If I pulse aggresively up to say 20 or 30 mph and then pop into 50+ mpg and maintain or glide to the next stop, maximizing regen when it is inevitable that I will have to stop, I can keep a full SOC and average over 50 mpg for the trip, regardless of how many lights we hit. I guess what I am saying is that how long you use assist, or how long you stay below 50 mpg has a much bigger effect than how many bars you use. This also seems to be true for regen as well. Always try to enter regen as early and as agressively as possible when it is enevitable that you will need to stop. This ensures that you don't use the mechanical brakes and lose that energy. I always accelerate going down hill or on the flat for an upcoming hill, as the amperage used is much less with gravity helping you and then ride the momentum up the next hill. It is not uncommon for me to be able to go up most if not all the next hill at 50+ mpg. If I have to accelerate I do it aggresively for a short period and try to glide the rest of the way again. The bottom line is to manage the SOC properly and use the assist to the maximum advantage where it makes sense. All of my best trips end with the SOC at 7 bars or over. If you don't ,manage the SOC the computer will hit you with a big time forced regen penalty that makes it impossible to get anything over 50 unless going downhill while it is active.