I think there may be a couple things going on as in reading your notes, I know I have managed to confuse myself between your comments of 120V vs 240v devices, and “one side” of a 120v leg and then the half reported wattage of your 540watt radiant floor etc…
What many of us have seen an experienced especially in early days are 240v devices only having one leg of the 240 picked up. So a 3500 watt hot water heater appearing as a detected device of “hot water heater” showing 1750w, and then the other half appearing in Other.
I think that is what we are all assuming you are talking about, but now looking at that screen shot a bit closer, I see where this might be something totally different and i’m wondering if there is a red herring in all of this making it more confusing.
Your heat pump. I get what you are saying about the numbers not adding up if heat pump were only half, but I would then say - are you sure that the device called Heat Pump is what you think it is? Is it possible that some part of your heat pump at either 2700w or 5400 watts? I’m not sure if you named that Heat Pump or if Sense did, but even if Sense names something, take it with a grain of salt. Most likely unless its a simple device with only one component (a space heater, pump, vacuum etc…) Sense probably only identified a part of it. Is it possible that Heat Pump isn’t the device you think it is?
Similar question for your Oven. Is it a 3500w heating element? or is the tag on the oven for 3500 watts combined between heating elements? Only able to draw from personal experience, but my oven has vastly different energy draws depending on cook temperature, if its pre-heating vs broiling etc…
While I realize that the “Now” tab isn’t direct from the device and is routed through the cloud, I don’t think anyone here has ever seen the bottom right corner number be wrong. You mentioned that when you plugged your 1500w heater in, you did see the that number adjust the amount you would expect. So let s assume that that number is correct.
Regarding the floor heater - If you turn it off for 30 minutes, do the ~215w pulses stop on the power meter? And then if you turn it back on, do they start up again?
When you were under the floor and saw it pulsing to the 540watts you expected, were you turning it on and off, or is that its “regular” pattern when its heating? Or had you just turned it on, so it was working harder to get to temp? I don’t know a lot about electric radiant, but I’m just thinking about my induction cooktop. Depending on heat setting, it both varies in frequency between pulses, and amplitude of the power draw. Is it possible that your floor regulates these things based on a temperature probe? Ignoring the 200w labels on the power meter, if you turn the floor off, does the instantaneous power meter in the bottom right corner drop by about 550w?
Last question because this certainly is odd. I would assume that support would have checked this, but can you a look on your phone in the Sense app - Settings/My Home /Sense Monitor and see if the information under Signals looks correct? If you haven’t discovered this page before, it can be helpful for troubleshooting and device detection because it shows you power and voltage per leg. Which leg you ask. I’ll save that for another conversation, but just know that yes, people have asked for these to be labeled and presented in the info panes of detected devices.
This turned into a much longer post than I intended. I’m trying to break down the issue a bit and see if they are connected or not because it does feel that either you have some compounding issues, or you are having an experience that no one else seems to have had.