Well Master Guns I don't call what I do a "Beer Gut Cut" because that is what UK calls the feature they will do as an option at extra cost.

What I found when designing kilts is that almost all kilts can benefit from having the waistband sloped. The back higher than the front.

Now all my kilts incorporate Slope. How much depends on your particular shape.

Try this - wrap a bath towel around yourself where you would like your kilt to be. It doesn't matter if that is Traditional or Mid, or even Low Rise. Wherever you like wearing your kilt.
Then move around a bit, bend and sit. Let the towel settle to where it naturally wants to sit.
Then get a pencil and walk up to a door frame and mark the height of the back of the towel on the frame. Kinda like you used to do to measure your kids growth. Then turn around and make a mark at the height of the front of the towel.

Now step back and look at the two marks. That's your slope.

As far as I know, I am the only kiltmaker that uses slope. All the kilts I make use it and it is a standard part of my measuring system. I don't charge extra for it.