在上一層 = in the storey[floor] above.
在下一層 = in the storey[floor] below.
在下兩層 = in the storey[floor] below the storey[floor] below.
在上兩層 = in the storey[floor] above the storey[floor] above.
above the above = 上兩次
參考: Really pure Me. Don't give to copying people [全自己。 別給copy的人。]