At your consumption rate of 327 Wh/mi, I have a few questions and maybe one thing to research. First, I know it has been "cold" in California, so are you using heat? The heater can use a few miles per hour of range, and it's most noticeable when the car is cold and you initially warm it up. But that should impact both cars pretty equally.
The P3D has a less efficient motor in the front of the car, so you're not only using more energy when driving, but you're using some of it less efficiently compared to the rear motor. There's not much you're going to do about that. Try putting the car into "Chill" mode and see what you get?
During a road trip in my P3D, in 40-50F degree weather, I was getting around 295 Wh/mi with the heat running and one seat heater on it's lowest setting. A quarter of that drive was in the rain, so I probably could have done a bit better, but this was driving 75-80 the entire time, so I think 295 is very good for what I was doing.
If you aren't accelerating hard, the heater isn't running high, the weather hasn't been very rainy, and you're driving long distances at at time rather than short drives, there's something you may want to consider having Tesla look into. There is a service bulletin they've issued for battery packs produced within a certain date range. The bulletin states that some cells may not be connected properly, leading to abnormal range. I don't know whether it would show up as high consumption, permanently missing charge, or what, but either way you might want to have them log into your car to see what's happening. They can likely do the diagnostics remotely, so it shouldn't really inconvenience you at all.
Good luck.
