estimated original gravity vs final abv

When looking at the design tab in beersmith, for the majority of my recipes there I about a 4-5 point difference between the estimated original gravity and the estimated ABV. I am trying to understand why this is.

4 to 5 points difference from what?  Are you looking at the original gravity estimation and comparing that to the ABV estimation?  As in 1.064 = 6.4 to ABV =  6.0?

While there is a direct relationship between the potential ABV in a recipe as defined by the sugar content (original gravity) of the wort, the ABV is also influenced by the mash temperature (giving a variable amount of fermentable sugars vs. higher dextrins) and the yeast strain used (differences in attenuation between strains).  Further, actual fermentation temperatures will either maximize or minimize the activity of the yeast within the normal range of that yeast's attenuation range.