This is approximately what the pattern is saying. I think you'll find that at the ends of the bind off rows you'll have one fewer sts to purl because you'll have one st on the right needle leftover from the bind off. The armhole should measure 8 inches at which time you start the bind off for the shoulder. Did you start the neck bind off at the correct measurement? Does the pattern say anything about working the shoulder bind off at the same time that you work the neck shaping? There may also be a difference in your row gauge and that recommended in the pattern but this is perhaps less likely.
What is the pattern name or can you post a link to it?