When Curved Ramp 26 display is set to "Symbolic", then Above / Below line type and pen settings don't work. When display is set to "Projected" (or variant), the user has no control over Break Mark, Walking Line, Start / End Symbols.
We agree that this use case needs a better solution and we consider one in a later version.
But in the meantime maybe this finer workaround might help overcome the issue:
The cut plane height needs to be set a little bit above the lowest point of the object, on the lower story. This can be 0 if the object is placed to -100, or +100 if the object is placed to 0. If you place the object on the upper story, you need to calculate this height based on level height, object height, and placing height on the home story. Regardless of placing the necessary height needs to be set on the lower level.