Higher pressures can result in a bumpier ride, if your road surface is rough. If it helps, think of the max pressure as what you'd run if your roads were smooth as glass. When you rough up the surface, you let some air out to absorb the chatter.

The point of diminishing returns for softening the tire is the point at which your rim starts pinching the tube on bumps and causing flats, or where your tire starts to roll a bit on sharp turns, but generally, softer is comfier.

Cfd's advice looks sound.