To answer OP's question:
2.5% dilution is crazy high. I would either (A) ask Blackstone to retest, or (B) check for mechanical problems. Even if you are doing lots of short trips I can't see it being that high. I think the truck is running extremely rich or has a leaking injector. Is your gas mileage suffering lately?
Nope. We just completed a long road trip and it got the same 18-19mpg it always gets on the freeway. Doesn't smell rich, no extra soot on the tailpipe, none of the other signs of it running rich.
Could it be Blackstone misreading the fuel level? Maybe I should go with Polaris next time.