Yes, the bind off 3 (4, or 5 for different sizes) is the armhole edge, nothing that abrupt happens at the neck edge.
- Is the ssk the neck edge decrease?
[B]Armhole and V-neck shaping[/B]
Place marker at neck edge. Bind off 3 (3, 3, 4, 5, 5, 5) sts at beg of next row, k to last 7 sts, k2tog, 5 sts in Seed St.
On this first row you are beginning at the underarm and you do the BO there, then work across to the neck and that last part is the v-neck shaping there: " k to last 7 sts, k2tog, 5 sts in Seed St." You are doing the decrease that makes the shaping just inside the seed st border. On this row your neck decrease is the K2tog and since you do all the decreases on the RS, the other neck decreases are also K2tog.
Then you do a purl back row, keeping your borders as established.
Then it gives you the next RS row:
Next row (RS) Work 4 sts in Seed st, ssk, knit to last 5 sts, 5 sts in Seed st.
Again this starts at the underarm and here you seed st over 4 stitches and then do the SSK which will be your underarm dec each time, then knit on across to the last 5 sts and do the border seed stitch.
So the underarm side dec is always a SSK and the neck side dec is always a K2tog.
Now you keep decreasing both sides by this plan:
Repeat dec at neck edge every 4th row once more, then decrease 1 st every other row 11 (12, 13, 13, 14, 14, 15) times more. AT SAME TIME repeat decs at armhole edge every other row 5 (6, 7, 8, 9, 12, 13) times more. Work in this manner until armhole measures 7½ (8, 8½, 9, 9½, 10, 10½) inches, ending after a WS row.
You don’t repeat the neck decrease again until the 4th row, but you do the armhole decreases every other row(so every RS row) from the time you start them until you have done all of them [5 (6, 7, 8, 9, 12, 13)]. After you have waited till the 4th row after the first neck dec, do the decrease again at the neck as well as the armhole decrease. So for several times you will be decreasing at each end. You complete the underarm decreases first and then keep doing the neck ones until you have done them 11 (12, 13, 13, 14, 14, 15) times.