Originally Posted by SteveKnows
I have been letting the car warm up say 10 minutes - before driving it out of the non-heated garage
I think we've found the biggest reason your fuel economy is low. Unless your backing out of your garage onto a major highway where you have to seriously stand on the gas to be safe, there is no reason to warm up the ICE. I push the start button, place the car in gear, release the brake and I'm on my way under electric power. The ICE starts up after I've already moved a few feet. Keep in mind that you aren't putting any real demand on the ICE until the needle on the eco gauge moves into the power section.
Additionally, you'll get better fuel economy when the temps warm up and you can get gas that's not the winter blend. Also, short trips are mpg killers.