Ginger Saison Recipe From Extreme Brewing

Hi everyone - I'm about to start my third batch of extract brew. I recently downloaded brewtarget, and after inputting the Ginger Saison recipe from extreme brewing into the program, the estimated OG, FG, and ABV it calculated are much different from those listed in the book. I would have thought these calculations would be pretty standard for extract - anyone here have any idea what's going on? I've listed the fermentable ingredients below. Thanks!

Ginger Saison

1 lb caramunich barley
6.6 pounds light lme
1 pound light dme
1 lb light belgian candi sugar (added late)
2 ounces crystalized ginger
WLP 565

According to the book, it should be:
OG - 1.072
FG - 1.015
ABV - 7%

According to Brewtarget, I get:
OG - 1.066
FG - 1.020
ABV - 6%

FWIW, I've noticed that brewtarget sets the default "yield" of LME and candi-sugar at ~78 percent. Is "yield" in this context the same as efficiency, and if so, is there a reason you wouldn't get all of the sugar you add to the wort via extract? I've tried playing around and changing it to 95% in the brewing program, and my calculated OG's then become way to high compared to the book's OG's.

Thanks for the help!

 

I made a all grain version of it, so I'm not much help. I will say that I would double the amount of crystallized ginger. I didn't taste it at all in mine.

 

I've read that in other posts about this recipe. I was thinking that I would follow it as written and "dry hop" with some more ginger to taste after fermentation is done.