I have never been able to figure out the instructions for that side of the apron either.

However - to me it looks as thought the reverse pleat in your instructions is what I call the under apron pleat, which makes for easy climbing of steps, hills and vaulting of gates for me at least, and it also gives material to allow the aprons to fall modestly between the thighs when sitting.

There doesn't seem for there to be anywhere else for that pleat to go but where it is laid, and the Velcro has to go.

I would detach the Velcro and put the pleat under it.

Before you sew it, though, make sure that the pleat lies right when the kilt is being worn. For my kilts I have to raise the inner edge of the pleat so that it does not roll out from under the edge of the apron. Different kilts have different amounts of lifting - probably due to slight differences in where the outer edge hits the body.

I end up with a slender triangle of two fold fabric raised above the waistline - it is easily hidden in the waistband, and the edge of the apron stays neat.

I also find that the fabric folded at the waist to do the shaping of the edge of the apron has to be allowed to drop down below the waistline, or it tries to pull the lower edge of the apron narrower.

The inner edges of the aprons are the most fiddly part, but they only need some of logical thinking to get right. Or rather to get tho the point where you can start to experiment with solutions.

In most engineering, if it looks right, it is right.

Anne the Pleater