My refractometer reading HAD to be wrong...right?

Brewed a beer meant to be 1.041 OG, based on a 71% mash efficiency, which is a point or two more liberal that I sometimes get. However, a chaotic brewday meant that I forgot to pull a sample of wort before it went into the carboy w/yeast, and all I had left was the pre-boil sample in the refrigerator. A preggers and sickly wife took my attention later that evening, and I forgot to use the pre-boil sample to check my mash efficiency. I checked it several days later, took a drop out of the frig, and it read 1.053, which is WAY higher than anticipated. Yes, I did a 90 min mash, rather than a 60 minute like normal, but that was the ONLY dift. thing. Since I didn't have a correct reading, I can't tell how much alcohol will be in this beer, but doesn't my reading almost have to be off? I wouldn't think an extra 30 minutes would account for a 12-point jump in mash efficiency....

It just sux because the beer that was supposed to be 4% and quaffed in 18-oz tulip pints for the equivalent of 'one beer' could now, depending on my evap. rate be up closer to 7%...

 

I wondered about the temp...I pulled the jar straight from the fridge, dipped a knife in it, and dropped a drop or two onto the refractometer (at room temp), left it for about 10 seconds, closed the slide, and measured....I figured that would have been fairly close to 60 degrees...maybe I was wrong?