Create Floor on any Level other than Level 1

It is easy to create a floor on level 1 in dynamo. I have done this numerous times.
It seems to be impossible to create a floor on level 2. I changed the code below to specify creating a floor on level 2. But it creates a floor on level 1. Anyone have ideas how to correct the code below to create a floor on any level other than level 1?

I think there is a level offset value so try to add this.