You are definitely right - Sense detects individual components for HVAC systems. Sense originally found my Furnace Fan, but not the draft inducer. I eventually put it on a smartplug and saw what the fan detection was missing. Even before I had it on a smartplug the furnace fan was showing up most of the time with my AC as well, but not always.
I think my AC detection picks up both the AC compressor and compressor fan at the same time, about 3000W with a 5000W spike at the start.