Need help understanding part of a pattern

Pattern (baby sweater) says: P28, cast off next 6 sts, P59 including st used in casting off, cast off next 6 sts, P to end. I don’t understand the “including st used in casting off”. What does this mean??? Thank you!!

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When you work the stitch over stitch bind off for the given number of sts bound off there will be one stitch remaining on the right hand needle. Count that stitch as you purl the next 58sts so that you will have a total of 59sts on the right hand needle.