The purpose of the 6 rows is to slowly decrease the crown, then drawstring off. The use of flat knit is when those spaces between the decrease are filled in once the hat is taken off the loom and the crown is stretched to set the flat knit. If you don't do the slow decrease this is what the crown ends up looking like.
You will notice the center is smooth yet the area around the center is wavy. So by the process of doing the 6 rows before the draw string, and stretching the stitches out after taking off the loom gets you a very smooth result when placed on the head.
FGDSBO: Fine Gauge Drawstring Bind Off: It consists of 6 rows.
Row 1: K1 D-> toss bottom loop over, K2 Repeat all the way around ( this means every 4 peg should be empty.)
Row 2 and 3: K only pegs with stitches
Row 4: K1, K1 D-> toss bottom loop over, K1 Repeat all the way around (this means every other peg will be empty
Row 5 and 6: K only pegs with stitches
Now to drawstring, send the tail through every other stitch in round 1 all the way around, then in the next round send the tail through the stitch left. Drawstring together starting to tug on the inner circle 1st then the outer.