I should have mentioned that out the gate Paul, .....Z4000 amp meters are known pathological liars,....I know mine lies to me constantly when compared to my fluke meter.....I’ve seen this amount of variation lots of times,.....if you can’t see any mechanical issues, and the loco runs smooth, then yeah,...perhaps as the other posters mentioned, break that slower in some more to loosen her up, and lash away buddy,....like I said before, if you lash them up and they ain’t fighting one another, then let em eat,...
Pat