the light is fine to run for autos, in the future i would pick up a bigger light. what you want to look for is the par reading :
PAR, which stands for Parabolic Aluminized Reflector, bulbs produce about four times the concentrated light intensity of general service A shape bulbs and are ideal for recessed and track lighting. Like all light bulbs, the numbered value (i.e. PAR 20 and PAR 30) represents the diameter of the bulb in 1⁄8 of an inch. Therefore, a PAR 38 would be 4.75 inches in diameter. LED PAR light bulbs provide a directional output and exceptional beam profile characteristics while using only a fraction of power.
lux is a great number but go by par, a 450 watt led should be hung above the tops in veg at 18 inches (45.72cm) and 14 inches (35.56cm)
so yes the 20cm is way too close and you will end up burning your plant.
with par values you get that by flowing the directions of the maker you could even lower the light if you need to.
i hope this helps