Well, we're not quite on track with the thread title here, but that's not out of the ordinary from my board experience in other areas.... What I'd ask is: Did you boil the dickens out of this wort after over-sparging? I did that to a batch and got a lot of kettle caramelization, leaving less fermentable sweetness. I'm fairly confident this isn't your case, else you'd have mentioned that the wort was darker and more molasses-like than expected. But it's better to ask than not.
I've not yet done a WLP565 batch, but I have a vial in the 'fridge. I have used 566 and 585 with light worts and have obtained pretty stiff attenuations (> 85%).
Another thing: I'm not overly experienced, and I ask questions that I've learned to ask as a result of that experience. I learned by being confused by it that there is a pretty big temperature correction you may need to do if your sg is measured fairly hot. Did you do that correction for your near 1.055 OG? If yo measured it quite hot, then you could have another 5-10 points of OG. Excuse me if you learned that at your mother's knee, but I didn't.
Boiled off a little under a gallon. Used a refractometer for measuring.
did you take your fg reading with the refractometer as well? if so did you apply a correction for already fermented beer? in the presence of alcohol the refractometer will give an inaccurate reading. However there are tool on line to correct for the error and get the true gravity.
a 1.012 un corrected works out to closer to 1.000 corrected.
I used beersmith's conversion tool for fermenting beer.
ahh well, took a shot
I got excited for a second thinking maybe I missed something, but no.
I cracked a bottle yesterday, 2 days after bottling and it already had some carbonation going on. Not sure if this is a precursor of what's to come, because I typically let my bottles sit a week before checking them.