You can build the value of the repairs up. For example, the repair costs are almost $11,000. Do they expect supplementals for undiscovered damage. Add this in. Do they owe you a rental car (no rental if the car is totaled)? If so, determine how long they anticipate to repair the car and multiply this by the daily cost of a rental. Example, $11,000 plus a $2,500 supplemental plus 15 days of rental at $35 per day and you have a cost on repair in the $14,000 range.
Now take the cost to total. Say the value of your car is $24,600. If they total it, they are going to sell it to a third party as salvage. Say $5,000. Say the diminished value of the car (assuming you are entitled to this in California) is $6,000. Their net out of pocket for totaling the car is now $13,600. Particularly if they expect supplementals they would be more inclined to total out the vehicle rather than face the uncertainty of repairs.