Galaxy Pond Pale Ale Recipe question

Hello everyone,

I'm a all grain brewer and i want to brew a mash of the Galaxy Pond Pale Ale which is top rated on this site.
I have some doubt concerning the amount of Pale malt required for this beer. The recipe says it's for 5 gallon and 9lbs 12.6oz of malt seems a little too much, by my little own experience.
What do you think ?

When i download the recipe in Beersmith 2, it says put 16 qt of water ( 15 liter, I'm French so i use metric system ^^) for the mash and 6 gal for in fly sparge. I don't understand how you can use 6 gal for sparging if you want to have 5 gal at the end. It also says that the estimated pre-boil volume is 8.12 gal :  can 3 gal evaporate by boiling ?

I think the quantities are wrong, but since i don't have much experience in brewing my own beer ( i usually brew all grain kit), i want to have opinion on them.

Thanks for reading.

I use eight to ten pounds of grain on the average five gallon batch.

The total weight of grains in this recipe is 10,81 lbs, which is quite above average but might be correct, you're right. But what about the water needed ? It doesn't it seems to be a lot to you ?

I generally use 1.25 quarts water per pound grain in my mash, and 6 gallons for my sparge.

You don't have to use all the water.  I regularly leave a couple gallons behind. But by then there's very little sugars left in it, so it doesn't matter much. Law of diminishing returns and all that. 

With my setup it's not unusual to boil off two gallons or more. Seriously. I start with 7.5 gallons or so, and sometimes have had to add water at the end to bring it up to my 5.5 gallon target. 

Why 5.5 instead of 5? Loss from sediment left behind when racking.