Some background. I own a housecall repair service, and put around 24K on a car in a year. Since I go to customer's homes, my typical driving day has between 3 and six cycles of: 5-10 minutes of residential neighborhood driving, followed by 15-20 minutes of highway driving followed by 5-10 minutes of residential neighborhood driving. The topography is fairly hilly here in metropolitan Pittsburgh. so there are lots of quick ascents and descents in the residential neighborhoods and lots of long, slow ascents and descents on the highways. I purchased a very gently used 2007 package #1 (I think) lease return in March of this year, with 33K on the odo. It has been a ball to watch my own retraining in action. When I started driving the Prius, I managed about 42mpg (only double the average mileage on my previous car, an '03 4-cyl Accord), and have watched this climb steadily to about 52mpg on average over the first 9,000 miles. (MFD numbers only) I've been lurking on this board for quite a while, and have read the P&G and SHM articles several times as I got better at driving the Prius-way. I've found that there really aren't many opportunities for P&G, save occasional residental stints where there are no other drivers to worry about. I've increased my mileage largely by utilizing the "no arrows" condition while coasting down a long hill on the highway, followed by green arrow, battery-only speed maintaining on the flats. I also use the red arrows, ICE-only-charging-the-battery mode whenever possible. This, combined with more awareness of upcoming traffic flow has earned me my first 10mpg increase. So, finally to my questions: I've noticed that on some drives, my car just doesn't want to hit the no-arrows condition (is this WS?) when going down a long descent. Feathering the pedal back as gently as possible finds the car moves directly from battery powering the wheels to regeneration mode. Gently increasing acceleration then moves directly from regeneration to power. If there is a no-arrows interval at all, it is split second, and no amount of trying seems to find the sweet spot. It's as if the difference in pedal position between right and wrong is a millimeter's movement - just not maintainable. Conversely, on other drives, WS seems absurdly easy to maintain. There must be an entire inch of pedal play in which the car stays in WS. You can keep it there almost by ear. The length of descents where I have trouble are long enough that I don't think the problem is coolant moving to the thermos. There also doesn't seem to be any condition that is common (SoC low, engine cold or warm, outside air temp cold or warm or hot, degree of slope, etc.) I usually just resign myself that the car "doesn't want to" at that time and stop trying - I have to pay attention to the road after all! I also think that if I could figure this out, I could approach 60mpg, so I'm posting here. Any ideas anyone? Thanks!!