Re: Survey say's.......
I know a number of surveyors that do stand by their work, what none of them really can do is insure they didn't miss anything. There are just too many places that a hidden defect could be that you just can't get to without destroying the boat.
I have been sailing since i was 2, working on boats since I was 12, spent years working in a boat yard, then on a big budget racing program, and now work in maritime law, I have even helped some commercial surveyors in the past. Yet when I bought the new boat I got a survey and he found things I missed, but the guy we used is a professional who works at his craft. On the other hand the guy you delt with sounds like a quack, and in my eyes should be personally shamed.
I would get in touch with SAMS, and BoatUS, and any other surveyors organizations and file a complaint about this guy. Missing a hidden defect buried in the bilge is one thing, miss counting how many and of what type of extinguishers is another completely.