Getting a pretty bad 340-370 Wh/mi efficiency on a new P3D+ with no mods when going 75mph on highway, 45F. Surprised by this. At this rate the snow tires should get much better efficiency. I wonder if it's just the tires.
Lowest average I've gotten is 284 Wh/mi on a lower-speed (~60mph) drive, so it doesn't seem like an outright mechanical issue.
I was in the same boat as you (AWD 19” rims, but non performance).
I was averaging 342 wh/mile until I hit over 500 miles. Seems to be some kind of a break in period. I’m guessing it’s the tires.
Once I hit 500 miles I drove 100 miles on the interstate at 75 mph with 260 wh/mile. Also at 55 degrees I’m seeing really good efficiency, at 45 degrees I see a huge spike in consumption.