Did Dave say that there was anything odd about the car and/or tune when he was done? It would be worth contacting him to see what his thoughts are and also find out some baseline numbers for his dyno so you have something to compare to. He's a good guy and I'm sure will help you out.
You could also try taking a couple datalogs and throwing them up in this thread. We'd be happy to take a look at them for you to see if anything jumps out.