Some take longer than others. There some XL yielders (autos) that take a few extra weeks, maybe you have one of those?
you should give them as much as you can give them up to 800-1100PAR (to simplify) without added CO2. Give both lights unless it's over that value or too much heat or some other negative isn't worth it. (common sense, i have no idea what your previous light was or specs of either one. so, do the algebra on what you have as it might be worth it.)