I'm totally lost on this one-- I just took out a calculator and started from the beginning, and it just doesn't make sense. For the small size:
You start with 111 sts. You decrease 2 sts (2) , then dec 2 sts every 10th row 2X (4), then every 8th row 6X (12), then every 6th row 5X (10). This is a total dec of 28 sts, which is what they tell you. Fine.
But then it says "Divide for Front and Back: Working front decs as established"-- as established how??? Those 2 sts every 10th row 2X and then every 8th row 6X, etc.??? That sounds like a very uneven front edge to me, to keep changing the number of rows between dec rows.
You then bind off 7 sts twice (14), maintain this mysterious "front edge as established", and dec 1 st at each armhole edge 6X, which is 6 sts, but this going to give you a total decrease of 9 sts on each half of the front because of the front edge business.
So from 111, you lost 28 sts from the first dec rows. Then 14 (2 x 7)from the BO sts, 12 for the underarm decs (6 for each one) , and supposedly 6 from these front edge (3 on each) decs you were supposed to continue with. That leaves 51 sts. Then you get to the Back, and it wants you to dec 1 st at each armhole edge 6X. That's 12 more sts, which leaves you with 39. Later, they give you 31 sts across the back with 5 sts for each shoulder-- which is 41. Which you don't have.