Everything in Stair Body JM9a still applies.
Major feature added: You can choose to have the stair cut by the Floor Plan Cut Plane. Recommended.
With the 'Auto' cut setting, you can choose to show a Cut Fill instead of the cut line. This will show the true cut thickness of the stair, similar to the roof element behavior.
Minor feature added: Separate cut line switches for the above and below stories.
