Yes it seems due to the military continuing to add yardage to their kilts through the course of the 19th century more of each pleat's cloth would be hidden in a fold underneath.
I think that "box-knife pleat" name makes sense because the pleats look like box pleats on the surface but are sort of knife pleats (all the pleats overlapping in one direction) underneath.
Proud Mountaineer from the Highlands of West Virginia; son of the Revolution and Civil War; first Europeans on the Guyandotte
