I have found that this is a most difficult car to diagnose. On my car I average 28-32 almost every day but my variables are surely much different from your own. The routes you drive and the time driving you cannot do much about. The Escape really gets awful mileage for the first 10 mintues even if you let it warm up. I do not know why and I have not been able to change that. If you drive for short commutes your mileage will be down even on the highway. I also live on a hill but the trip down and back up mostly evens things out.
Some of the variables you can control. First you must rest your foot on the gas pedal and just massage it, not really push it. It helps to get up to speed as soon as possible but start to let off when rpm gets near 4k as though you were helping it shift, trying to help it reach its 'sweet spot' on the tach. I brake often when I can because on my Nav I can see the battery charging. That is the key to staying in EV as long as possible (possibly giving you a good feeling but not the best MPG because immediately your mileage will go down while recharging the battery). I can stay in EV up to 40
MPH and most often can make it kick into EV at about 15
MPH if the battery is full. I can go up to 3 miles in EV and more if downhill. The key is real gradual acceleration.
It seems that the colder your outside ambient temperature the lower your MPG. Never use the fan or any of the temp controls in orange (unless you must use defrost). I match my Nav mileage against gas in/gas out and it is about the same usually. Apparently the lights and radio and wipers run off the 12V battery because they seem to make no difference in charging rate, night or day.
I understand what you say about slowly accelerating and I believe you but this car drives like no other. My best guess is that your commutes are too fast or too short to get a full charge to the battery pack. Let me know if you are getting your info from the Nav display or the gauges.
Mike