Is Hopville wrong?

Hello all,
I recently discovered hopville and have been happily tweaking away with it's recipe calculator. I was just browsing the featured recipes when I noticed that none of the OG,FG, or ABV calculations in them seem to match mine. For instance, this recipe:
http://hopville.com/recipe/1102225/blonde-ale-recipes/dirty-blonde-ale

By my calculations, the expected OG should be 1.063, but hopville claims 1.059.
((6×45)+(1×28)+(.5×34))÷5 = 63

Likewise, the ABV calculation at the bottom doesn't appear to use any of the numbers on the recipe page. Using the page's listed (OG-FG)*131.25 yields a different number, as does the same calculation using the listed attenuation.
Is hopville an inaccurate source for brew calculations, or is my math wrong?

Thanks

Well it doesn't seems that your maths is wrong. Then why it is so?
It has confused me also.

I have noticed it, too.
I brew session beers, and I can't get the abv to dip below 3.0 on the calculator. I can modify the gravity, but the ABV stays put.

Is the "mash efficiency at 75%" your actual efficiency or is that the percentage that Hopville is using to calculate your gravity?

I am just wondering since that seems like the only "variable" in the whole problem that may be giving different numbers than what you have!

Good luck in figuring this one out!