Open Buildings - Energy Simulator - Common Partition Walls/Internal Floors/Ceilings

Good morning,

I hope this question finds you well.

I have a little red cross next to the internal floor and internal ceiling surfaces for my ground floor and first floor 'adjacent' rooms. What is the reason for this and will it prevent me performing calculations? (I haven't got round to performing calculations yet)

Clearly a ceiling to one room is an internal floor to the one above. Does the construction type of the ceiling have to be the same as the internal floor?

Lets say I define the internal floor construction for the first floor room as [outside] plaster/concrete/screed/ceramic tiles [inside] (this would account for the ceiling below as well in my case), the ceiling construction for the room below should be nothing as I've defined the entire floor/ceiling combo within the internal floor above? If I had the internal floor as [outside] concrete/screed/ceramic tiles [inside] and the ceiling construction below as just plaster, does the software combine the U values of the internal floor and ceiling?

With partition walls it makes sense as the partition wall for each adjacent room is the exact same construction type and it is a 'common surface', by that logic, do I have to have the same construction type for the internal floor and ceiling for it to be shared correctly as a common surface? If they're defined the same is this what would make the red cross disappear?

Hopefully this makes sense, your help would be greatly appreciated.