[Wien] the parameter of denominator in the file of case.in5

[Zhou Bing]

Dear all, 
According to UG (p.119), the first three lines in the file of case.in5 determine the plane for plotting electron density, however, I do not understand the parameter of the 4th column (denominator): is it arbitrary? how to determine a proper denominator?
Another quesiton is that it seems the number in 4th row (x, y, z nshells) do not change the plot, am I right?
Any comments, suggestions and instructions are highly appreciated!
Best wishes,
Bing