When your car is totaled by your or the other insurance company it can be frustrating. The insurance companies are only required to give you the current value of your car minus any prior damage and your deductible. Typically an insurance company will total a car when damages exceed 70-80% of current value.
Once an insurance company has come up with a value for your car they will make you an offer, if you have made any recent repairs to your vehicle for example new tires, engine work, new battery etc be sure and present those receipts to them. This will help some; however, not dollar for dollar. If the company has provided a rental car during the process they will cut off the rental car after presenting the offer, typically 2 or 3 days later.
The evaluation performed by the insurance company are pretty thorough, if this is the other insurance company you are dealing with perhaps you can obtain your own insurance companies claim departments opinion, this assumes have full coverage on your vehicle being totaled.
Best of luck, if have further questions contact Flanigan Insurance at 314-727-6000.