Tom N has the best advice. After all, if just running tires at their max inflation was the best for safety and performance, why do ALL manufactures bother to publish weight/load ratings?? Heck, fire all those high paid engineers and save some money!
Inflating a tire to is recomended pressure for the load is the only thing that makes sense. If bumping to the next level on the chart makes you sleep better at night, then go for it.
After all, have you priced new tires lately