Millennium Rooms- Continental deck - around stairs

[2CoolCanucks]

I was wondering if anybody knows the difference between a class 11 and a class 12 room on the Continental floor of the Millie?

As well, there are 4 rooms around the stairs mid-ship (are we allowed to post a link to a pic?) and they appear to be smaller than the other inside rooms on that floor. Does anyone know if they actually are smaller?

 

The other inside rooms say that they have 170 sq. ft.

Do these four rooms have 170 sq. ft as well?

 

Would the noise of the stairwell affect those rooms?

Has anyone ever been in one of those rooms around stairwells??