Lol, how many fish do you see looking straight up at the light? It's fairly uncommon, even for my surface feeders. They look up just long enough to feed and then go about their day. They don't care what position the light is on the rest of the time.
I have a section in my tank with floating plants that blocks out quite a bit of light. It covers about 1/4 of the tank currently (75g tank). Plus there are spots where my taller stems block out light and also where the light just doesn't shine because it only covers part of the tank (low-medium light). Ergo, there are plenty of swimming spots that have little to no light in the tank, but my fish still prefer to swim where the light is directly shining. If it really mattered to them, I'd think they would stay in the less intensely lighted parts of the tank.