so just how much will this new set move when fully loaded if it moved almost 1/2" empty ?
1/2" in the opposite direction ?
i can see the rubber moving some, but 1/2" seems excessive.
i wonder what the factory tolerance may be ?

as to the 1/2". a few years ago, the local chevy dealer received a new hunter frame machine. the representative was there to demonstrate new features and teach the techs how to operate it after the factory installed it and got it operational. the subject of the teaching demonstration was a new, just received, 4 wheel drive pickup off the lot. when it was checked, it was found to be over 5/8" out of spec [i forget which way] ! it was taken on a short drive and went down the road perfect, but to see that being a ton out from factory specs brand new was shocking to say the least.
it was checked several times, and the frame machine was re-calibrated several times as well, so the results were true. it was also checked a few times with strings and levels, and the results were very close to the machines measurements.

bottom line is, what do you expect to happen when loaded, and if remeasured changes again for the worse, can you reset it more to your liking ?