Look at the swatch photo for the profile. The chart's shape/dimension is not accurate.
THESE NUMBERS DO NOT PROOF FOR MY FRAME. The numbers must be reworked. The pattern of increases is absolutely correct and will stand as a base for the technique.
When the work reaches the icord caston at (and all even rows after) row 4, knit one row of icord, wrap the first stitch on the body (purl stitch) to anchor the icord to the body and knit a second icord row.
Caston is 8 stitch icord.
Shown with a cast-on count of 0 stitches.