Rowan pattern question, Jude sweater

I am thinking there might be an error in the pattern, but I wanted to be sure because I am not an advance knitter. This part of the pattern is to shape the shoulders and back neck. There are 19 stitches on the needle.
Next row (RS): Cast off 2 stitches, K until there are 5 sts on right needle and turn, leaving rem sts on holder.
Work each side of neck separately.
Cast of 2 sts at beg of next row.
Cast off rem 3 stitches.

Now, if there are only 5 stitches on the right needle and it tells me to cast of 2 and then cast off remaining 3, why didn’t it just say cast off 5? I’m thinking maybe there should be a “Work 1 row” in between those two cast off lines because when shaping the shoulder, the pattern reads:
Cast off 2 stitches at beg of next row
Work 1 row
Cast off remaining 3 sts.

Do you suppose there could be a mistake in the pattern? Thanks so much for any assistance.

You can only cast off at the beginning of the row, so in essence you do work a row between the cast-offs when you purl back.

So cast of 2, finish the row, purl back, cast off the remainder