I'm making a sweater and ready to pick up and knit to begin the sleeves. The pattern states to place markers 6 1/2" below each shoulder seam and pick up and knit 58 stitches between the markers. Do I have to pick up and knit a stitch into every stitch. To get 58 I have to skip some if I am to go down 6 1/2" from each shoulder seam. If I need to put a new stitch in each already knitted stitch, there would be 72 stitches. Can I skip some when picking up and knitting?