Please help with pattern . Casting off shoulders .

[Barmyleyther]

Please can someone explain what this means think I'm reading it all wrong .

I have 30 rows .Cast off the armholes on either side every row as follows : 1x5sts , 2x3sts , 3x2sts, 1x1 sts .

In the meantime when you reach 37 rows , for the neck miss the middle 18 stitches .

[Granny Square]

Welcome to the 'ville!  Is this a vintage pattern?  It is odd to use the term 'cast off' in crochet, but I think I may have seen it in a really old pattern.  In crochet, it usually means either to finish off or slip stitch across.

Just from general knowledge of how shoulders are usually either shaped straight across or with a slight downward slope toward the arm, my educated guess is that, across the outer edges of your piece :

1x5sts=slst across 5 sts for 1 row

2x3sts=slst across 3 sts for 2 rows

3x2sts=slst across 2 sts for 3 rows

1x1 sts=slst across 1 st for 1 rows

Then, at row 37, you miss the middle 18 stitches; I assume row 37 is somewhere in the above.  It is very common for instructions for armholes and neck opening to have an an instruction that says 'at the same time', meaning 'now in addition to the armholes, we are going to deal with the neck hole in the middle'.

Usually in my experience when you reach the bottom of the neck, like your row 37, you will stop working all the way across and just work from neck hole to armhole on 1 side and finish off the yarn, then re-attach the yarn and work the other side to match (the pattern should tell you).

Does the pattern have a diagram, a sketch of the outline of the pieces with measurements perhaps?  If so, looking at that might help you visualize this.

[Granny Square]

Here is a tutorial, or rather a description and diagram of different sleeve types - scroll down to "set-in".  Usually for set-in the bottom of the side shaping is just for a few rows and then straight to the shoulder, but you can see how on this example the neckline is rather low, but it shows that you are eventually, sooner or later, run into the neckline when you are working the sleeve opening.  

This same shaping for the body piece would be (typically) very similar for a conventional sleeveless top.