^^^ All that you said is not true. The pressures the graph uses is all about the 15% drop zone where the best handling and wear is supposedly taking place. More and more pros are once again going back to that same graph and altering only slightly at about 5 psi more then recommended. There are exceptions, just like anything, if you're riding on cobblestones then you may want about 10 to 15 more psi to prevent pinch flatting, but since very few of us do that then the graph is correct.
The rack with panniers is nuts, think about what you said. Loaded panniers have weight thus you must calculate the weight of the entire bike with all accessories you would need to go on a ride, whether touring or not! Thus if for example the panniers, rack and gear weighs 65 pounds then you need to add 65 pounds to the total bike weight. If the weight changes same thing. And if your touring then you are probably using heavy thick tires and heavy thick tubes which means there is far less air loss day by day vs racing tubes, and there is far more leeway in the psi you can handle vs racing/training tires before a pinch flat occurs.
Also keep in mind, as pros are going back to that chart they may alter their tires 5 psi more for better handling as I recall doing back in the early 80's, but there are people who want more comfort and could care less about performance so they might want to drop their psi by 5 from the chart.
At the end of the day it's up to you how you want to run your tires, if you don't like the graph then forget it and do whatever pleases you. I know from experience of racing, and riding mountain roads that the graph worked the best for handling and tire wear. Take that for whatever it's worth.
Here's more on this:
http://www.biketinker.com/2010/bike-...-for-bicycles/