Curious about this myself, I did a bit of Googling and came up with this from: http://www.celticislesshop.com/highl...asurement.html

"Really like the tartan you selected but think it would look better if the stripe was on the edge of the pleats ? This is called PLEATED to STRIPE and not all tartans will Pleat to Stripe. Most popular pleating is to the SETT, so the pleats and the front of the kilt look the same. Additionally, we'll need to know which color stripe in the Sett to pleat to if you desire a "Pleat to Stripe" kilt. Kilts pleated to the stripe may incur an additional charge depending on the tartan (sometimes takes more fabric). Casual Kilts are not available pleated to stripe."

So, it seems as though it can sometimes take more material to pleat to stripe.

Mychael