This is the problem with off the rack Kilts.

The waist has to be some measurement and the hip have to be some measurement larger so the maker must decide an "average" or "Standard" for their product.

If you are lucky or "Average" the Kilt may fit fine. But it's a crap shoot because each manufacturer uses a different dimension.

this is the reason custom made Kilt will always surprise the customer because it fits so well. And they have probably never had a properly fitting garment before in their lives.