Leveling floor with cement board

[Dumbo]

What is coring a hole in them?

The reason I made that comment is as @Plan Tec Tiling said . No board manufacturer would ask you to do that I am aware of .

 

[Slippery]

This is such a confusing read from start to end.

Sure is, had to check whether I was high or not, and I'm not!!

 

[Tile Marble Granite]

Sand and cement based substrate.

That's what I thought, just was not sure. Thanks!