I have a bit different perspective on placing a cutting mat on an ironing surface. I do it all the time.....but.....
My ironing surface is very lightly padded - only one layer of Warm and Natural batting - over a plastic trash bag (to prevent moisture from steam warping the board) and then topped with 1 layer of silver-colored ironing board fabric. This thinness makes a very suitable pressing surface for quilting because it gets the seams nice and crisp. It also is not too thick to take a cutting mat as there is little give under it.
Go for it, you'll be fine with one table if the ironing is done on a very flat surface.
Jan in VA