If it blocks the screen ... it's the wrong height ...
The answer is "it's what works for your setup".
Many have been happy with it just above or just below the screen.
Some have sworn that for big screens that 2 centers are best: one above and one below.
Sometimes a virtual center is what works (In my family room in my old house a virtual center bested using the VP180 hands down). The 180 is a great speaker but just wasn't working for that configuation & room.
So ... it's what sounds best ... make sure you try all the seats.
P.S. play with the 180's tilt (you may need to aim it up or down depending).
