Relay weights different on my truck?

The op asked why the difference. The first thing I said was LOAD SHIFT, then expounded on the other differences and why weights will rarely match up between drivers on a relay. At no point did I say that the truck/fuel/5th wheel changes the trailer.

And I didn't say change the tandem settings, I said change vehicle placement on the scale. Try scaling with you steers at the back of the platform, then again at the front. You will get the same gross, but different axle weights. I've done it to get a legal cat scale ticket.