As Scott said, over feeding your corals will lead to water quality issues. It is the same as feeding any other food. I over feed my tank on the 2 days a week that I feed my corals. I mix a blend of phyto and zoo plankton, both live and freeze dried. I turn off the main pump and leave the ph's runing for a ˝ hor to an hour, then turn the main pump and the PS back on. The skimmer goes nuts clearing up all the leftovers. During the time the pump is off the tank is a bit cloudy from all the particles floating around. I can see all the SPS
polyps feeding as they close up around the food.
I don't target feed as there is no need with this method, but I do have a large skimmer and lots of macro algae in my sump.
More than twice a week may be overdoing it. Keep checking your water parameters to make sure you are not spiking on ammonia, nitirite or nitrates.