You are correct Jimmy.
As an example, my own kilts are 38"x44"x22" using my measurment system.
The apron is 14" wide at the waistband and 17" at the hem.
That kilt contains 6.71 yards of fabric 22" wide.
Pleat reveal is 2" with a depth of 4". Or 10" from knife edge to knife edge.
The apron is 1/3 of the total waist measurment versus 1/2 as in a traditional kilt. That was necessary due to the side pocket placement and the button closure. I found that if I tried to make the apron any wider the buttons looked funny and the apron puckered badly when sitting. Also the pockets wouldn't go in without sticking your hands under the apron.
So my apron width is a compromise. It seems to work. An added advantage is that the apron can fall between the knees when sitting and squatting without pulling. A good modesty point for those not familiar with sitting in a kilt.
The only thing I'd like to change is to decrease the pleat reveal to 1". I chose 2" from looking at other casual kilts and thought, at the time, that was normal. I've done a prototype with a 1" reveal and it looks great but can't change over completly right now because I have too many kilts on the order board and am swamped. Maybe next year I'll release the FK 'traditional' model. That kilt, in the same size, would use 7.71 yards of fabric.