Is that also just a simple matter of moving the buckles a couple inches?
No, actually, it doesn't work well for making a kilt bigger. If you move the buckles to make a kilt bigger, you can't move them much before the underapron starts to show, which makes it really obvious that the kilt is too small. If you move the buckles to make it smaller, the only indication is the lack of symmetry across the back of the pleats.