Nah, having them closer to the walls like that is perfect. You're not getting a hot-spot down the center now and you should see very even spread that way.
That's a often accepted misconception yes. Still a misconception though.
You ARE losing more light on the walls with the lights closer to the walls. So you are giving the plants less light overall. That's a given.
When you have good distribution you don't have a hot spot with properly spaced out light sources either. Not one that matters anyway. So there is no point in losing the light for "better" distribution since the light was already distributed adequately.
That's the bit people fail to understand though. It does'n have to be 100% the same intensity everywhere. 80% of the average intensity as minimum is the accepted rule of thumb . It's just not worth it to make it "better"beyond that. Professional growers don't
Only when you try to utterly max out the light intensity would it make sense to waste more light on the walls to get that little bit of extra light to the sides. When growing at "normal" intensities it's wasteful to do this.