That kind of stuff is more about what a light can actually 'put out'...if you can, download the phone app Photone, from there you'll need to buy (but really cheap at 6.99$) the profile for the type of light you're working with. That will tell you the PPFD and DLI readings you're getting at the level of the top of the plants. Seedlings want something like 200-300PPFD (MuMols) and once you get them a bit bigger you're looking at 300-600 in veg and then 500-1000 for flower. Raise or lower your lights to achieve these readings.