As Jock says, pleating to sett is a fairly modern thing, early C20th, possibly the very end of the C19th.

Pleating to stripe was first been practiced by the military and can be traced to at least c1796 and a Gordon Highlanders' kilt now on display in Edinburgh Castle.

Early civilian kilts, those c1800, seem to have been pleated as it came so to speak and often there was no attempt to match to anything but by about 1810 civilian pleating started to follow the military practice of pleating to stripe. Bear in mind that most kilts were box pleated at that time and so it was the only way to pleat uniformly with less material.

Most kilts require more material to pleat to sett and as a result the amount of material 'in a kilt' has grown to the point that there are still some kilt makers that insist that to be a 'proper' kilt it must have 8 yards of cloth. Of course if you actually measure an 8 yard kilt you will often find that it has less depending on the sett and size of the individual.