Probably position. In my old kegger the evaporator was on the back wall and the back kegs would be 5-7F colder than the front ones. This did have some pluses.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk