hmmm now I'm confused lol I think though if I'm thinking this through right that they are saying the same thing even though the arrow looks like the stretch is suppose to be length wise it ends up being width wise cause you don't put it on the way its layed out if that makes sense. The stretch ends up going around you and baby not up and down once you put the sling on. I think lol. Honestly what I would do is take the peice of fabric tie a knot it it where the seam will end up being and try it before I cut and sew see which way it ends up stretching once on, does that make sense? I really suck at visual layouts and usually do better if I just play with the fabric to figure out what I want it to be doing.
good luck
Janessa