If the left edge that shows in the picture is the neck edge, then that's right. But the bound off stitches should be going the other way. The BO for the shoulder shaping is done at the beginning of the row that's the armhole edge, not the neck edge.
The neck edge is on the right side, but with the row you told me to make a plain row gives the arm hole a big slant. I think we need to leave that "follow" alone and not make a plain row because it throws off the slant. Shoulder shaping is going up from the arm hole.
Not having the pattern, I wasn't sure where you were. Usually the first dec is on a RS row, just so long as it's at the neck edge. According to the pattern you dec on 3 rows at the neck edge. Then skip the dec on 1 row and dec on the next row at the neck edge. And so on. The key is 'neck edge' that's the edge you want to be making the decs on. If you're at the armhole edge, you don't decrease there.
Sorry if you think I misled you, I was just trying to interpret what you wrote. Okay, here's that section -
"Shape neck: Next row: Cast off 10 sts. Pat to end of row. Work 1 row even in pat. "
You do this cast off on a RS row, finish the row, then do the WS row.
"Keeping cont of pat, dec 1 st at neck edge on next 3 rows, then on following 2 alt rows. 17 (20-22) sts. Work 3 rows even, thus ending with WS facing for next row."
So the decs start again on the RS row, dec on the WS, then the RS row. Do the WS row with no decs, Dec on the RS row, plain row for the WS, and dec again on the RS row. That should put all the decs at the neck edge. Then working the next 3 rows would be WS, RS, WS and start the armhole BOs at the beg of the RS row.