Jerry - Your company is giving you good advice and posters who say otherwise are not well informed on this subject.
Diminished value payments are common in automobile accident adjustments, the theory being that a wrecked vehicle is not worth as much as an unwrecked vehicle. While we all understand that a properly repaired vehicle is as good as an undamaged one, the plaintiff attorneys disagree with us, as do millions of Carfax customers.
Also referred to as "diminution of value" (lawyers like to speak a different language donchaknow), many states require it to be paid by the insurer to the claimant. Georgia, for example, has a formula that prescribes DV by statute and it is required to be paid to damaged claimants. In the terminology of auto claims the insured in this case is the drunk (who is also a claimant but may not be entitled to DV) and the claimant is your wife. If not required by statute in your state, many insurers may still pay a dv settlement just to avoid litigation.
I have sold over 200,000 insurance total loss vehicles in my career (about 13,000 in 2005 alone) and deal with auto adjusters from a broad spectrum of companies on a daily basis. Also, the Trac was hit on I-20 last year and the insurer paid my estimate (not theirs), a rental car and DV. I didn't even ask for the dv, but they were complying with Georgia statute.
Your agent is giving good advice and should be able to assist you further in geting your settlement.
Curious, which companies are on each side. I only ask becasue some companies are far more combative and aggressive than others.