Shape shoulder help

I am shaping a shoulder for a sweater it says bind off 9 sts at beg of next row, them 10 sts at beg of foll alt row. ending with WS facing for nex row 17sts. I cannot follow this. Can someone explain this to me in English.

BO 9 sts (RS), work to end of row.
Turn and work across (WS).
BO 10 st (RS), work to end of row.
Turn. WS is now facing.

Presuming these are the only BOs needed for shaping, you should have 17 sts.

cam

Thanks. Perfect. I appreciate your help