I had good correlation between my 2 AC units and the first two AC devices my Sense detected last fall after I did a data reset. But a year or so later I have accumulated 5 AC devices. The interesting bit is that all the Sense detected devices have some correlation with the actual running of my AC, just at different time in the year. I’m guessing my AC signatures look different in different seasons.
Here’s the thread that compares Sense AC devices against Ecobee hourly cooling runtimes.