Finishing edge of hood

Below are the directions for finishing the hood of my DS’s sweater. I get it all up to decreasing the 16 stitches. What I don’t get is why you continue the 6 rows after that before you bind off. Shouldn’t the rib be the actual edge? And what do they mean “sew rib/roll front”?

Thanks!!!

Edging With smaller needles and RS facing, pick up and knit 155 (155, 155, 169, 169, 181) sts around edge of neck and hood. Work K1, P1 Rib for (2) (2½) inches. Dec 16 sts evenly across last row of ribbing, and work 6 rows Stockinette st. Bind off on 7th row. Sew rib/roll front at center neck, overlapping center front (left overlap for male, right overlap for female).

Are you supposed to sew that as a hem on the inside of the ribbing?