I'm really stupid, as you say the height of the rooms should be set at 320 cm.
Problem solved, thank you very much!

Hi,
after creating a model with some levels, on 3D view I've found the floor shadow on the ceiling.

Here the some examples:
https://www.mediafire.com/convkey/62f1/xs3syb8nbucqtj76g.jpg

https://www.mediafire.com/convkey/e6f9/7m9cncjbsevrpov6g.jpg

And my levels:

https://www.mediafire.com ...