Welcome to the new forum! We upgraded our forum software with a host of new boards, capabilities and features. It is also more secure. Jump in and join the conversation!
You can learn more about the upgrade and new features here.
The ABV is capped based upon the maximum tolerance of the yeast as published by the manufacturer. Some of the data that comes embedded in BeerSmith with regard to the yeast alcohol tolerance is from well over a decade ago and may have been updated by the manufacturer. I recommend checking the manufacturer's site or data sheets for updated specs and adjusting the yeast profile as needed. Most manufacturers do have some safety factor in their published specifications, so you may be able to obtain a higher value than published.
You can always trick the program by changing the upper limit yourself, but realize that you may not be able to attain to those results.
To change the yeast profile, double click the yeast then click Edit Details.
Under Properties is Alcohol Tolerance. It is almost certainly set to 10%.
Change that to whatever you want. I use 20% for US-05 when working on a recipe.
As Oginme advised, this doesn't mean that is what it will do, just a value to enter to allow the recipe to calculate a potential.
I searched around and found folks claiming to get 15%-17% on US-05. Good enough for me.