"Ceiling values may not be changed..."

[Katalyst777]

Your Floor Defaults aren't set correctly for what you want, based on your description.

You should go in to your Floor 1 Defaults and set them to the highest Finished Ceiling Height you'll have on the first floor.

Do the same on Floor 2.

Then reset to defaults, and go back through all the rooms on Floor 1 and set their Finished Ceiling heights to be lower, if that's what you need in those particular rooms.

Repeat for Floor 2 and you should be all set.