I'm wondering if a non-knitter typed up the pattern from hand written notes and mis-read K5 and P5 as KS and PS, because replacing 'S' with '5' in the instructions does make the stitch count work out. That could also explain why there are no special directions in the book for those instructions.
An English Knitter (nationality and method).
FO: Downton Hat
Call me either Clutter or Julie (my real name), if you find it easier to type than Dclutterchique.