Algae is the key, not the fact corals are animals. I have done experiments on terrestrial plants in which daylight hours were extended- and there is notable changes in output with increased daylight. The key is balance- if the algae are over illuminated it will harm the coral- this is usually true due to wattage though as opposed to saturation over time. The key issue is that all plants need down time- amd the only way to tell is to experiment. Be forwarned though that not all corals will respond equally, it might do great for one at 24 on 12 off and might kill another at 15 on 8 off. I would stick to nature as it works, but if you want to push the envelope a frag tank is ideal. 99% of what is good in this hobby has come from such experimentation.
