I really wouldnt be worried if I were you. 6k lumens just means better penetration into your canopy during flowering, With the extra lumens you could raise the light and spread out the plants so they get more light down lower during flowering.
During veg you will just get some really fast growth, and lots of big strong shoots.
Generally noone is going to be using too much light, you are just losing efficiency.
There is such a thing as too much light and the plants will start to "bleach out" and get white and faded, but this is rare. Chances are the extra lumens will just be wasted on the upper parts of the plant, and help penetrate deaper to the lower branches.