Ginseng Ficus Rapidly Losing Many Leaves

Hi my ginseng ficus plant has been losing a ton of leaves lately but at the same time I see new growth.

I got the plant 3 months ago and was told at the time it only needs water about once a week to keep the soil moist. I also have light shine for about 12 hours a day on it.

I suspect I may be watering too little but I am very afraid to overwater and cause root rot.

What are some recommendations? Please see the pictures attached.

Hello David
I can´t see any saucer under the pot ?! If you watered there once a week, without a saucer and want to keep the woodtable in good condition and clean, i think ... you definitely watered to little. In the wintertime or not growing season , it´s better to water the ficus a few times less, if the ficus grows more water will be required.
How much water do you give him ??
Also the location looks not very bright, the ficus needs al lot of daylight, do you think the growlight is strong enough to replace that, can be.. can be not ?!

Is there any drainage holes in the pot?