expydaddy, if anything, if your truck is empty, you should have 35 in the front, 30 in the rear. The tire pressure should be reflective of the weight that the tire sees. The more weight, the more pressure (assuming the same tire all the way around). Not to mention, that the sticker you are looking at only applies to the factory tires. Once you start switching up brands or going with a different style tire, the pressure requirements are different.
Keep in mind too is that when your truck was built, that was just before the whole Firestone issue and it was proven that Ford was recommending too low of air pressures for tires to give a nice ride. The true test is to get some colored paper and put it in front of your tires. Now, using some white chalk, coat the tread of the tire. Now, drive forward to let the chalked part of the tire run over the colored paper. Did the tire leave a complete imprint of the tread on the paper? If yes, then you have the correct pressure. If you notice that the tread is a little light on the edges, then you need to back off on the pressure a little bit. If you notice that the tread is a little light in the center, you need to go up in the pressure (but not to exceed the max rating of the tire). If you had to adjust the pressures, repeat the test and see if you have them set right.
In an ideal world, when you load up your truck from a nearly empty state to say 1,000 pounds in the rear, you should be adding a little bit of air pressure to the rear to help ensure that the tread remains completely in tact with the road. Since you are putting more weight on each of those tires, you are risking the tire flexing up in the center, resulting in excessive wear on the outside edges of the tire. This is especially true when you have a truck like a single rear wheel F-350 and you are dropping 4,000 pounds into the bed.
