I think the independent adjuster is correct. I have heard that some people even replace drywall when the prior resident was a smoker because it's hard to get rid of the smell. Even with paint. I used an independent adjuster for damage that was not fire related a few years ago. I had to pay out of pocket for the fees but in the end it was worth it. Insurance only wanted to offer me 15k for damages and the adjuster got me 300k (which was the actual cost of repairs) and everything was repaired and done right. My heart goes out to you.