My Song of India (Dracaena reflexa) has brown spots but I certainly am NOT overwatering it. It has 2 hours of direct sun and 10 hours of artificial lighting. I water it about every 9 days, or when the soil is 2" dry to the touch.
Chances are very good that it has been over watered in the past or is currently getting too much water. Check this question and answer for more details.
The Song of India has moved around in its classification from the Pleomele to the Dracaena genus. All the Dracaena have thick fleshy roots and are able to withstand dry situations. In an indoor location it needs bright filtered light. You may think the 10 hours a day of artificial lighting is sufficient but without a light meter it is hard to tell.
The symptoms of too little water would be the leaves lying flat against the stem and the entire leaf gradually turning brown and papery from the bottom of the stem up.
Spotting on the leaves is usually an opportunistic fungus/bacteria. The telltale identification of fungal action is the centre of initial spot is lighter than the periphery and the spot spreads out. This is the growth pattern of the fungus at work.
Increase the light levels and intensity and decrease the watering. Fertilize very lightly every other watering and the plant should be able to outgrow the fungus.
Once you have new growth you can remove the diseased leaves. Also remove any dead leaves from the pot.