"As needed" is going to be all day, every day for plants grown indoors in winter, Pamela. You're really underestimating how much light these plants need, I think. If you start moving them around and giving them a couple of hours here and there they will not be happy.
Tropical plants, even the ones that take some shade outdoors, get very bright light and have long days - even in winter our daylight down here in Florida are lasts a couple of hours longer than further north.
