If you read my posting carefully, I said that my efficiency as calculated by Beersmith is always around 70% and the grain bill in these recipes is always 2+ pounds too much. I was simply suggesting that new AG brewers trying these recipes should be cognizant of this.
Estimating gravity is pretty straightforward and we can assume both Brewing Classic Styles and Beersmith 2 are accurate. I have not entered a BCS recipe and compared the gravities based on the same efficiency settings though. If you have and are saying that Beersmith 2 is always estimating a higher OG, then it would be of interest to investigate that.
It should be noted that each of these "tools" base the estimate on the potential extract of a specific grain. If the grains selected in Beersmith have a higher potential than those used in BCS, 70% efficiency will yield a higher starting gravity.
For example, a 1.039 OG using a PPG of 34 for 5.5 gallons with 70% efficiency is 9lbs of grain. Changing just the PPG to 36 needs just 8.5lbs of grain. A 1.091 OG using 34PPG is 21lbs of grain where 36PPG is 19.8lbs. We can see a a bit of play in the estimated gravities.
If a brewer wants to use a recipe from Brewing Classic Styles, they should follow the recipe on their system with their process and see how it comes out. No two systems are the same and no two results are either. If it is of interest to the brewer, they should take careful notes and readings to determine their own efficiencies and choose to alter the recipe for the next brew.