Sue has the key to why you are not getting the count right. Seed st 3, * k2, lift the second one from the end over the end st for the bind off, k1, lift the second st from the end over for the bind off. K14 repeat the bind off as given at the *. K14, BO2, K14, BO2, for the last buttonhole and there will be 2 stitches at the end, do them in pattern.
When I did it on paper I had it wrong, but worked over the 59 sts it came out perfect. If you have an extra st just work it in pattern as Sue said.