Formula for Estimated Final Gravity

Hey all, I really love BeerSmith2 and am trying to understand it better by learning how the various fields are calculated.  I've got many of them figured out but am stuck on the estimated final gravity.  Could someone please help me with this?  Here's what I've got so far (I'm doing these in Excel):

Inputs:

Calculations:

But my estimated final gravity (EstFinalSpecificGravity) doesn't match BeerSmith, which gives 1.010 (and it varies more widely in different scenarios).  Please help!

Perhaps a more extreme example would be helpful?  This one looks so close that it could almost be explained by a rounding error.  (I know, it probably isn't that simple, but it's close.)