If you put them near the HID, no they will do nothing. More watts does not equal more available lumens. At any location, a plant will see the brightest available light and nothing more.
However, if you add them to shaded areas around the perimeter, they will then be the brightest light at those locations, therefor increasing usable light to the plant = more yield.
Keep them close. Intensity diminishes greatly at distance. This is particularly true for flouros. If you can't notice the plant material looking brighter with them on, they are doing nothing.