This is excellent advice but be aware that it could take as much as a year (maybe even more) to get your money if you have to go the court route. Therefore, keep that in mind when you make your decision as to whether or not the 85% is acceptable or not. Since your car is perfectly drivable 15% might be only a few hundred. Is that worth waiting as much as a year or more? If it is, then go for it. If it is not, then consider accepting the 85%.
Excellent point. But there is another side to the coin. A lawsuit in small claims court is an expensive hassle for an insurer. The insurer owes a defense for its insured. The insurer would have to hire a local attorney or send an employee (from Chicago?). Texas Rules of Civil Procedure 500.4(b) allows a corporation to be represented in small claims court by an employee, owner, officer, or partner of the entity who is not an attorney.
(Note: Chicago and Texas gleaned from Mark_A's post down the street.)
Insurers don't like to admit it but the potential cost of litigating a disputed claim is in our thoughts.
Strategically, file the suit and somebody at the insurance company will have to decide if it's worth the expense to litigate over a few hundred dollars.
Besides, small claims court rarely takes more than a month or two. That's how it's designed. Informal and fast.
And, as Zigner notes, the insurer pays the judgment.