Efficiency Questions

I did my first all-grain batch a few days ago and I just now got around to looking at my efficiency. With everything in ProMash, the efficiency required to meet the SG of the kit from Midwest I bought was between 53% and 61% to get a SG of 1.044 to 1.050. I didn't check my preboil gravity but my post boil gravity was 1.062. I ran those numbers though ProMash and came up with an efficiency of 75%. Have I done something wrong with my numbers? I was under the impression that batch sparging would yield an efficiency of about 66%. Here's my recipe:
10.5 lbs 2 row
.5 lbs Cara Pils
.5 lbs Crystal 40L
60 minute mash @ 153F
2 batch sparges
60 minute boil
1 oz Willamette @ 60min
1 oz Fuggle @ 10 min

Based on 36 ppppg extract potential from the 2-row and 32 ppppg from the cara and crystal, I figure you have 410 total gravity points in the grains. Assuming you ended at 5 gallons volume at 1.062, you got 62*5=310 gravity points into your wort.

That makes for a brewhouse efficiency of 310/410 or 76% efficiency.

Lots of batch spargers get 80% and above brewhouse efficiency. Your numbers look good.