we have been running 60/60 psi on the KO2's on our 2006 RB350 SMB. We have noticed the rear rides a little low so I looked at some tire calculator sites and they recommend more pressure in the rears then the fronts based on axle weights front and rear. An E350 typically weighs around 4500/5900 fully loaded which comes out to 49/64. I have never run an uneven pressure setup before, does this sound right? thnx