Update: Check's in the mail for the full estimated value of my S40.
What I learned: Forgo any decency with allowing the other insurance time to get back to you if their client is lawyered up or is slow to provide his input of events, like over 1-2 weeks. If you believe you're in the right and they're offering a raw deal, let them know that you're ready to take their client to small claims court. All the finger-pointing at the car ahead of us didn't mean a thing when the judge recognized a rear end collision for what it was. Once you have the judgment, get right back to the insurance to send the proof their way so they can send what the court has ruled for you.
Certainly a learning experience as a California resident.