When down to 10 (8) stitches, you will increase again back up to 22 (16) stitches to complete the heel section.
Right side: Pick up stitch at beginning of previous knit row. Knit to end, then pick up stitch from end of previous knit row (to 12 [10] stitches). Turn, purl to end.
Next row: Pick up stitch from beginning of row two rows before the row you last picked up a stitch from. That is, you will be increasing 1 stitch at each end of the knit rows, back to 22 (16) stitches, by picking up one stitch at each end from previous rows, going down two more rows each time. In final row, you will be picking up end stitches from the first heel row. This makes a heel section that “pouches out” from the ribbing and 10 (8) rows of knitting on the needle. Continue with body of sock thus: