Is there such a thing as too mich loght

I have a small 2x2.5 and do 1-4 plants max. I been using these Kessil H380 lights. Have 4 so it should be about 1000 watt equivalent in this small space. I been getting a minimum of between 1-2 ounces dried per plant with 3 lights (750 watt equivalant)), so was hoping for a bit more by adding a 4th. Looking into more powerful Blackdog and California Lightworks, but I think Im maxed out for my space. Might need to step up to a 2x4 and a bigger 6 inch fan/filter. As far as I can tell though more light is more flowers!

Those are like 6+ years old and run at 80w each, im thinking you could get away with 55+w/ft, why not try a run? Yes there is such thing as too much light but temperature & co2 isn't the same from garden to garden, so some can get away with more light than others.

2 x 2.5 = 5 sq.ft
80 x 4 = 320w
320÷5=64w/ft

Is there such a thing as TOO MUCH light?

Absolutely.

With the right light you could light up to 3x3 with the same power consumption and probably same fans and filter as your currently using and at least double your yield.