There is a mistake on decrease round 9, the correction is as follows:

Dec round 9 (dec): (K4, K2tog) 25 times, SSM. (125 sts)
Dec round 10: Purl, discard stitch marker.
Turn work and cast off using the picot cast off method on the WS as folls:
Cast off 4 sts, slip st on RH needle back onto LH needle, cast on 2 sts, then cast off 6 sts, rep from until all sts have been cast off.

Sorry for the confusion, Louisa