I doubt they total it. You are using your inurance company, which is good. They represent you, and are not spending their money, as they will bill the other company. You might be out your collision deductible until the claim is settled.
The estimate will go up as they remove sheet metal and assess the damage to the unibody. My 1 year old Acura was hit hard in the rear and shoved into the car in front of it, then hit again. I went through my insurance carrrier and told them I would not be upset if they totalled it. They did. The adjustor got to 60% of repacement cost and quit writing, as there was still more damage.
The other driver’s carrier also will owe you for a rental car. My company paid for mine and added it to the bill they presented to the other driver’s carrier. The rental car cost can help reach the threshold of a total loss. Insist on new parts. Tell the adjustor you will have the car inspected prior to repair, by a third party, for a second opinion.
Don’t forget to file for a diminished value loss. If repaired “perfectly” (no such thing), your car is worth less than an identical car with a clean carfax. Could be 20% of retail value.
I hope that you do not owe more than they retail value of your car. With a 1 year old Toyota, that’s unlikely. Loan and lease agreements often include GAP coverage for the amount between retail value and loan pay off. My settlement was $3000 more then the lease buyout, so my wallet got fat.