Since that is not the rated range information in the car (but instead from a third party app), I would not worry too much about it. What does it say in the car (not in the stats app) when you charge to 100%?
You are not alone. Quite a few people have reported similar fluctuations in range. However, not everyone is affected by this issue. For example, I haven't had any range reporting issues with my 8-month old RWD LR.
There is no official answer from Tesla. There are a lot of theories, remedies, advice here, but nobody really knows for sure why this happens to only some cars. Some people have tried pretty much everything to "recalibrate", but it hasn't helped.
I think the best thing you can do is to report it to Tesla. They may not attend to your individual request, but hopefully getting similar reports from a lot of people would get their attention.
You didn't say what model you have. Is it a SR+ or a MR? The battery health graph on the 2nd page is the one you should be looking at to get a sense of whether things are normal. And having said that, you shouldn't be concerned unless you have a sudden and dramatic 10% change in Rated Range.
What Stats shows in the upper right circle is what your car should be showing on the dash. The upper left circle is what it calculates based upon your driving style. Obviously, you're less efficient than the EPA rating, so your range shows 152m instead of 196m, probably due to fast driving, being in SoCal. Also looking down in the left corner it shows a Wh/mi of 322. That's also indicative of your fast driving. If you want to get the rated range for your vehicle, you need to keep the Wh/mi below 250.
I had this issue; my LR said 100% was 280 miles. I found hanging out for a week or two in 20%-50% battery range (charging only to 50%) and then finally charging to 100% (be sure to let it continue charging at 100% until it says "Charging Complete" This seemed to have recalibrated the battery and I had 305 miles at 100% again.
For me this worked when a 100%-5%-100% run did not.