Anyone here use a Fluker heat mat under their glass tanks?

In the directions it says:

"The heat mat is like a radiator, in that equal amounts of heat are radiated from both sides. Because heat is wanted in the cage, it is important that it is directed there. The heat mat should have expanded Polystyrene at a minimum of 6 mm thick, fixed to the outside surface of the heat mat. This will reduce wasted heat energy and will direct heat back into the cage. "

Then down under "Glass Tank Precautions" it says

" Ensure an adequate hole is cut in the Polystyrene to accommodate the terminal block. If this is not done, the base of the tank will be stressed and prone to breakage."

Here's where I'm confused.. I was told to space a glass tank up and so the mat gets air-flow.. This is saying to fix it to some styrofoam and put it right on the glass? What should I do?