I have the same problem with my truck and fiver. Our local shop tells me that a great deal of the new/newer trucks have the same problem and unless the trailer is so high that it compresses the springs on the back axle, it should be fine. Mine is about 4 inches high on the front compared to the rear and we have checked the axles for higher temps along with the tires and they are the same. On a trip across county in our car a while back you would be very surprised with the amount of nose high 5th wheels that we have seen. I am not saying that it is right but, it almost seems to be the norm with newer trucks.
Curly