Chris,
I don't know what to tell you. I couldn't find anything on the website about OG and FG readings. I would go by some style guidelines. As long as your total vol. was 5 gallons, I'm guessing that your OG wouldn't be as high has 1.100, cuz you're reaching some really high ABV levels.
Back to the hydrometer reading, though. Make sure you spin it when you put it into the wort/sample, and be sure to stir the heck out of it to homongenize it. I've had issues previously because the wort wasn't completely incorporated with the additional water. For instance, my Weizenbock, which was supposed to be around 8.2 and have an OG of 1.072ish read 1.049, and I KNOW that was wrong, because it tastes like alcohol and goodness, which I guess are the same. Also, use some 60 deg water to see if your hydro is correct. It should read 1.000 at that point.
Sorry if this is all reiteration of stuff that you already know, just trying to pass on some "live and learn" stuff so you don't have to.