You know I brought this up a while back, JB said not to listen to the voices in my head and all would be OK. I have my front centered right now and have no ill effects. All 4WD vehicles have the diffs offset from the factory. I don't know why, but they do. Now the front may be centered and the back offset or they may be both offset from the center of the vehicle, I don't know.
I know the rear end needs to be offset from the output shaft at the Tcase to the rear diff for your ujoints to work properly. Saw it on Extreme 4x4
Sorry, I know this didn't help you.