Note that you can repurpose the second set of Sense monitoring plugs using a feature called “Dedicated Circuit Monitoring”. I do this for my heat pump (a very efficient unit that has entirely unpredictable behavior from a Sense perspective). This monitoring works excellently for me.
See this forum post that gives some explanation of this feature.
Before they introduced this feature, I had essentially all of my “always on” devices on smart plugs (thereby tracking their usage), and all of my other commonly used devices were well detected by Sense… leaving the “other” category almost exclusively this one device. So, I could track it as essentially “Other”… I know this won’t work for many people, but it’s something to keep in mind if you are able to get most of your other usage tracked (though the dedicated circuit monitoring is far superior).