I guess the main factor here is whether or not you're trying to get every bit of PAR out of your lights that you can. If I feared that my lights were a little overkill for my tank, I'd try to raise them, or go to weaker lights. If I want to get all the PAR I can from them, I'll keep them as close to the water's surface as safety and sense permit. Remember that PAR diminishes over distance, whether the light is moving through water or air.
FWIW,
Mariner
It might seem par is getting over rated. Sure we need lots of power and high intensity to grow sps. My 250 14k phoenix is suspended 16 inches from my waters surface and I have never had more growth or color. Of course every tank is different and you should do what works for you.