It appears some errors crept into the pattern during the publication process. I’m sorry for this.
First, the RS and WS labels are reversed in the short-row heel shaping instructions. The last short-row decrease is worked on a wrong side row and when you complete the wrap & turn, the right side is facing you. The same is true for the short-row increases. The last increase is worked on the wrong side and when it is complete, the right side of the sock is facing you.
Second, the instructions for redistributing the sts after the short rows are completed and picking up the sts for the heel flap are also incorrect as they were published. Below are the original instructions that I sent. You should follow these instead of the instructions in the book:
Knit the next 10 heel sts onto the right needle. There are now 11 sts on the right needle (Needle #4) and 10 sts on the left needle (Needle #1). Remove the 19 instep sts from the waste yarn and divide them onto two dpns (Needle #2 and Needle #3). You will now knit in the round again. The beginning of the rnd is at the center back of the sock.
Knit the 10 sts from Needle #1. Using Needle #1, pick up and knit 3 sts along the side of the heel flap. Work the sts on Needle #2 and Needle #3 in the established Rib & Garter Stitch, beginning with Rnd 10 (when you work Rnd 1 of the Leg, see below, Needle #2 will begin with a purl stitch). Pick up and knit 3 sts along the other side of the heel flap. Knit the 11 sts from Needle #4.
The sts should be distributed over 4 dpns as follows:
13 sts on Needle #1; 10 instep sts on Needle #2; 9 instep sts on Needle #4; and 14 sts on Needle #4 (46 sts).
MORE ERRATA: The gauge should be 23 stitches and 28 rows in 4 inches (not 28 stitches and 28 rows).
Designer’s Note: If you have a small foot, you may be able to knit the pair from just one skein of Ultramerino 8.