First Partial Mash- 94.4% Efficient?? I don't believe it.

Did my first partial-mash tonight using the Death Brewer method after several batches of extract + steeping.

Followed his instructions with one modification that I did the 15 minute sparge + heated a tea-kettle full of water to 180 to rinse the grain at the end of the sparge (poured it into the grain bag).

Was expecting to hit 1.052-1.056 on OG and ended up at 1.062. My calculator is saying that I'm 94% efficient and I don't believe it. What am I missing here?

Full or partial boil?

Partial. Did just under 2 gallon for the mash - (~1.5 Qt/lb) did 2 gallon for the sparge plus the teapot of water for the rinse. Boiled the above and then topped off the carboy with probably 2.5 gallons.

More than likely you didn't get the top off water mixed well with the wort. It happens all the time.