After 7 years the battery appeared to be going flat, I drove to the auto elec... he loaded tested it and it looked perfect, the next day my ute wouldn’t start a friend had a micro jump start kit and said watch this...the ute didn’t start then after a jump start from another car my ute was in limp mode.... I then drove to battery world they also said the battery was perfect after a load test ... I explained it all again to the old fella there, he said leave your car here and come back in an hour ... one hour later the battery completely failed a load test, the replacement battery for the STX550 was $560 because its some flash battery 850cc ect, then I went to Nissan to have limp mode reset, perfect again
That might explain the difference in readings Amber if your ute sat in the workshop for a little while before the load test and if your just drove to supercheap and had an instant load test that may explain the difference