Peter beat me to it, but yeah - "what he said."

The first mentioning of pleating to sett in print is from The Kilt and How to Wear It by Ruardhi Stuart Erskine, c. 1901.
(I've got an article about that book here.)

He describes pleating to the sett as something rarely practiced but becoming more common. Little could he know that 100 years later it would be the norm!

When Peter talks about early box pleated kilts being pleated to stripe, this is what he means. This is a four yard box pleated kilt:


Here's a box pleated kilt made from six yards:


By contrast here is a modern eight yard knife pleated kilt pleated to stripe:

Notice the different appearance given by the narrower pleats of the higher yardage kilt.

What Peter says about pleating to sett requiring more material is generally true, but depending on the size of the sett this can sometimes be accomplished in a four yard kilt, as evidenced below.