Advice on Dogfish Head 60 clone

I put this in primary on 1-30-07. I kept the mash at 153 degrees, and used a washed pacman yeast with a starter. I was hoping for a f.g. of around 1.017-1.018 to have a bit of sweetness/maltiness to balance the hops. I've had trouble in my cool house (62-63 degrees) getting pacman (or even 1056) to finish below 1.020 for other beers. This time, I had an o.g. of 1.071, finishing at 1.010. Can anybody help me figure out why I finished so low, when I was trying to get it a bit higher?

13 lbs 2-row
6 oz Maris Otter malt

.75 Warrior 16.4% (continuous 60-5 mins)
.50 simco 12% (continuous 30-5 mins)
.50 amarillo 8.5% (continuous 30-5 mins)

Dry hop with .5 simco and 1.0 of amarillo.

Used 1.2 qts/lb at 170.1 to bring mash temp. to 154. Added a bit more hot water to hit the temp of 153. Let sit for about 70 minutes (sick kid to pick up at school!)Sparged with 170 water (batch, twice). Runnings never did drop s.g. much, so I stopped with 7.5 gallons of wort.

It does taste good, and I'm sure it'll be better after the dry hopping. It's a gorgeous pale color with a great bitterness. But, I'm hoping to figure out why it attenuated too well, so I can adjust for next time. Thanks!

Isn't part of the deal with Pacman that it attenuates like crazy?

If you want a higher FG (although not more sweetness, per se), shoot for a higher mash temp; 153 is still, just slightly, on the low side, i.e. above-average fermentability (moreso if it dropped much during the mash).

Thanks, bird! I guess I was thinking 153 was going to give me less fermentables, I didn't realize that maybe 158 would be better for what I was looking for. . Maybe I need to think about getting a new thermometer, too. I'm wondering how accurate it really is.

I've used pacman twice before, and even though everyone else said the attenuation was very high, that wasn't my experience before with it. This time, it really went to town!

Thanks again!

Also, your recipe didn't include any grain that would contribute a bunch of unfermentables. Adding crystal malts would have added a little more in there and made it finish a little higher.