Also have a 2017 XLE. 27.5 mpg on the highway is the best we have gotten. My wife drives it in town so I don't keep track, would like to think it is better than your 16 but wouldn't bet on it. They just don't get great mpg.
The problem with comparison here is that there is a lot of variation when people talk about "city" driving and this can greatly affect gas mileage.
Some people live in a less busy city and are able to keep their car at 30-40mph while driving around town. With some less populated areas, time spent idling their car is almost nil. Gas mileage here should be good.
Compare this to someone who is truly in a very busy urban environment where they might be idling their car at red lights, stop signs, or just sitting in busy traffic for over 50% of their driving. Gas mileage here can be truly horrible.
It depends. How long are your trips? If the engine is cold and I can't go two blocks without hitting a red light, I get 16-18 MPG. If it's hot, 20-22 MPG. If I can go 25-30 MPH for a mile or more without hitting a red light, 25-30 MPG.