Need Advice - High Attenuation & Low FG 1.002

I just kegged a blonde ale and it finished at 1.002. I calculated an approximate apparent attenuation of 95%.

I'm looking for some advice on what might have gone sideways to bring this beer so low and dry.

Too much 2 row?
Too low mash temp?
Probobly a combination of several factors.

Recipe:

Batch Size: 5.50 gal
Boil Size: 7.00 gal
Boil Time: 60 minutes
Efficiency: 70%
Pre-boil gravity: 1.037 (Target was 1.038)
OG: 1.047 (Target was 1.044)
FG: 1.002 (Target was approx. 1.008)

7.70 lb Pale malt 2 row
0.83 lb Carapils
0.55 lb Crystal 10L
0.55 lb Vienna malt

0.28 oz Centennial (55 min)
0.28 oz Centennial (35 min)
0.28 oz Cascade (20 min)
0.28 oz Cascade (5 min)

Yeast: WLP 001 Cal Ale (1L starter)

Single infusion batch sparge in 10 gal rubbermaid with false bottom
Mashed at 150 for 60 minutes

Thanks for any feedback out there. I'd like to brew this again this summer.

I fermented in temp controlled environment at 65 F.

Are you sure everything is calibrated right? That seems to be a pretty low gravity for a recipe with over a pound of crystal malt. You didn't mash particularly low at 150, either. My first guess would be a problem with your instruments, but I might be wrong. How does it taste?

Sounds like the recipe looks alright. Haven't tasted it yet, so that variable still needs to be checked.

I calibrated my refractometer just before checking FG, and then plugged reading into Beer Smith to adjust for presence of alcohol. I did not calibrate before checking OG.

Did you do a mash-out?

Sounds like a problem with your refractometer. Cross check FG with hydrometer.

Well, I actually tried to fly sparge for the first time with water at 168 F. This is my 4th AG batch and thought to try fly. No formal mash out.

Sounds like that might have been an issue and the mash was still converting?

I second JonK. Double check with a hydrometer. That recipe/method doesn't look like a likely scenario for 95% attenuation.

Thanks Jon & CP. I'll go back and double check for sure.

You guys were right. Went to double check. Hydrometer came in at 1.006 and calibrated refractometer came in at 5.50 brix = 1.007.