OK, I have to admit that I love the easy ones. Once I took a look at the starting gravity and the %ABV, the answer was easy to track down. BeerSmith limits the alcohol content based upon the maximum tolerance of the yeast. WY2124 is listed in your recipe at a max alcohol content of 8%. Recent spec sheet from Wyeast has it pegged at 9%. Even then, it will not get to the published numbers you have cited from the recipe. Lager yeasts are not particularly known for their ability to survive in high alcohol content beers. I am guessing that is why the WL833 is also listed. The program used the first yeast strain listed and pegged the max at 8%
You can adjust the max alcohol tolerance of the yeast in your recipe to get the numbers to match. What you actually end up with will be based upon the fermentability of the wort and how quickly the fermentation progresses. Once you set the max tolerance to 10%, you will get into the 1.035 FG range.
Irony is that I just brewed my doppelbock recipe this morning and pitched a double starter of WY2206 just about 2 hours ago!